UPDATE May 2022: I'm still a big fan of this product and have made a few updates to my initial review(s), but the bottom line is that it's held up to initial impressions. I ended up knocking off a star just because there are a few improvements that can be made, but it's still very solid.==============================I purchased the Fitbit Charge 5 as an upgrade from my Charge 3. I skipped the Charge 4 since I didn't really need/want the new features of that model, but the allure of a color display with the same lengthy, weeklong battery life was enough to make me upgrade to the Charge 5. I won't cover all the features of the Charge 5 since there are plenty of other places that go into great detail, and I may update this review after I get more use out of it.WHO SHOULD BUY A FITBIT CHARGE?The Fitbit Charge is great if your primary use is as a lightweight fitness tracker. I prefer the Fitbit Charge over the Apple Watch and other smartwatches due to its lightweight nature, weeklong battery life, and my lack of need for fancier smartwatch functionality. If you like the extra bells & whistles of a smartwatch and don't mind a heavier watch that needs to be charged every day or three, then you may want to skip the Fitbit Charge. Also, if you're a die-hard Apple user who needs integration with the Apple Health app, then you'll also need to look elsewhere because there's no data flowing between the apps in either direction; thankfully, the Fitbit app is quite good and does integrate with a number of other apps.IS IT WORTH UPGRADING FROM THE CHARGE 3/4?It mainly depends on how much you value a better, color display. The MSRP on a Charge 5 is $180 (though, I'm sure the sale price will drop during the holiday season), while the MSRP on a Charge 4 is $150; though, at this point, everyone's selling the Charge 4 (and 3) well below MSRP, especially if you buy refurbished.IMPRESSIONS:- Initial setup was fairly smooth. I had to connect it to the charger to get it started up. Transitioning from my Charge 3 to the Charge 5 in the app was easy enough. There was a firmware update notice (the firmware enables the EDA sensor), and that update was a little buggy & required a few attempts before it succeeded (at one point, I needed to reboot my Fitbit).- ECG monitor became available via firmware update 11/9/2021. I had some connection issues while trying to run it but got it to work eventually. I don't have any arrhythmia issues, so while it's a nifty feature, it's ultimately useless for me.- The Daily Readiness Score also became available 11/9/2021. It's only available for Premium subscribers. It takes 4 days before it starts functioning & a couple weeks to "tune". Overall, I'd say this is not terribly useful. If you work out on a consistent basis & get a decent amount of sleep, then it's always a great day to work out! That is, you'll remain in the Good to Excellent range (30 & above). For reference, I typically work out 4-5 days/week spending 30-40 min on cardio & 30-40 min on weights, which ends up being 110-160 Zone Minutes on those days when combined with whatever other Zone Minutes I rack up when not working out. But if you take a week off or so & return to working out, then you may dip below 30 into the Low score range where it says you should prioritize recovery. I also noticed that if you forget to wear your Fitbit to bed, it can throw off your score; it sent my score plummeting for no good reason otherwise. Also, perhaps not surprisingly, the Readiness Score seems to be primarily reflective of your cardio workout. It will classify my "Activity" as "Light" on some days when I spend a fair amount of time on weight training that doesn't really sustain an elevated heart rate (and less on cardio).- There's no longer a "home" button on the side of the display to "Return" or access additional menus. This took a little time to adjust to, but I'm generally okay with it, especially since the touchscreen is noticeably more responsive than the Charge 3. Now, you must swipe right to return to the prior screen, and you can also double-tap in most cases to return to the home screen; though, the double-tap can be finicky. Would I prefer to have a "home" button again? Yes. (Now, the sides of the device used for the EDA sensor & ECG monitor).- The display is much, much better than the Charge 3/4. Brighter with much higher resolution. and of course, color.- The display has 3 brightness settings; however, the difference between dim, normal, and max is rather subtle; they're all pretty bright, and this is unfortunate because it's a little too bright for dark rooms in my opinion. I liked the dim, auto, and normal settings on my Charge 3 much better. Hopefully, this is something that will be fixed in a future firmware update (assuming, the Charge 5 still has the sensor that allows for an "auto" setting).- The "up to 7 days" battery life is not a lie. The battery life lasts me about a week with my brightness set to "normal", which is the same as my old Charge 3. I do not use the built-in GPS nor the always-on display (both of which are a significant drains on the battery), but I do average 6-8 hours/week of active exercise time. And, since the "dim" brightness setting is bright enough for me, I use it all the time, which translates to even better battery life. Pretty amazing considering the brighter, color display.- The Charge 5 does a better job of automatically turning the display on at the turn of the wrist. My Charge 3 wouldn't always turn on or would require me to turn my wrist more than what felt natural. The Apple Watch is still superior with regard to automatically turning on when looking since there is a slight delay with the Charge 5 after turning your wrist (and, it still doesn't always turn on).- The wrist band that's included is a nicer feeling silicone material instead of the plastic one that came with the Charge 3/4. The "small" strap on the Charge 5 band is also smaller than the "small" on the Charge 3/4. On the Charge 5, I use the last or next to last notch on the band (i.e. the strap is basically at its largest, most expanded size), but with the Charge 3 strap, I still had 3 or 4 empty notches to work with. Not a big deal since they include small & large bands, but something to consider if you purchase additional bands. I did end up purchasing the Sport band, which does have more notches to work with. Be sure to use Fitbit's sizing tool on their website before purchasing extra wrist bands since they do vary based on which one you get.- The heart rate monitoring is nice & accurate like the Charge 3. I run on a treadmill with a Tickr X (1st gen) chest strap, and after the first few minutes of running when my heart rate is more stable, the readings between the Charge 5 & Tickr X are either the same or only off by a bpm or two. It's less accurate when doing sprints/HIIT since it tends to lag behind the Tickr X, but it's still in the ballpark (albeit, delayed).- The EDA sensor seems like a waste for me. Along the lines of the guided breathing exercises in the Charge 3, it's just something that I don't care to use, and I question its accuracy/validity anyway.- I'm not sure if this was introduced with the Charge 4, but there's a daily Stress Management Score now. The number seems fairly meaningless, since it's somewhat of a mystery as to how it's calculated. Yes, Fitbit tells you what the general parameters are (heart rate, sleep, activity) & premium members get to see how the sub-scores feed into the overall score (see below), but in the end, it just seems pretty meaningless to me.- I think this may have changed with the Charge 4, but it no longer tracks the number of floors you've climbed (no big deal as it was wildly inaccurate), and it counts Active Zone Minutes instead of Active Minutes now. Fitbit's website has more details on Active Minutes vs Active Zone minutes.- There's 23 clock faces to choose from. Most of them only display one stat (e.g. HR, steps, etc.) at a time (though, you can usually cycle through them all by tapping the screen), which is unfortunate. Hopefully, they'll add more data-rich clock faces, but overall, it's nice to see them making use of the colorful, higher resolution display.- The charging cable functions a lot better since it magnetically clips to the Fitbit (like an Apple Watch does to its charger). I believe it's the same charging cable as the Fitbit Luxe.- My Charge 5 somewhat regularly (once every day or two) has trouble syncing with the app. It has gotten better over time & usually just requires me to refresh the app (by dragging down at the top of the screen of the phone app). At worst, I'll need to restart the app, and once I had to restart my Fitbit device itself. Overall, not a big deal. Just an occasional annoyance.FITBIT PREMIUM MEMBERSHIP:I generally dislike paying for subscriptions since the cost of them can add up to something pretty substantial over time. The Fitbit Premium Membership isn't exactly cheap at $10/month or $80/year; though, you get 6 months for free with the purchase of your Charge 5. If you actually use many/all of its features, then it may be worthwhile, but for me, it isn't (i.e. I won't be paying for membership when my free trial runs out in a week or so). The Daily Readiness Score & Health Metrics Dashboard are the only premium features I routinely looked at, but I question their overall usefulness/practicality. Here's a rundown of what you get for your money:- Daily Readiness Score: see comments above in IMPRESSIONS section - in short, not terribly useful.- Health Metrics Dashboard (see attached pic): graphs/data for Breathing Rate, Heart Rate Variability (HRV), Skin Temperature, Oxygen Saturation (SpO2), Resting Heart Rate (RHR). The RHR data is already available for non-Premium users & you can view you most recent SpO2 reading on the device, but the rest of the stats appear to only be available to Premium members. The graphs are actually kinda crummy; there's two types: 1) one graph allows you to vary the time scale to view 7, 30, or 90 days, but you have to visually line up the dot with the values on the y-axis to determine the actual reading for each dot, and 2) another type of graph shows 7 days at a time with individual readings on the graph, but you can't change the time frame/scale of this graph. It would be a lot nicer if they made these graphs larger & interactive (so you could change the time scale on the fly & tap on the data points to see the reading).- Wellness Report: You can generate a PDF wellness report to be emailed. While it provides a summary of HR, weight, activity, & sleep trends over the course of 1, 3, 6, & 12 months, it's lame that you can't just view this directly in the app.- Stress Management Score details (see attached pic): extra details on your score including the sub-scores that feed into it: Responsiveness, Exertion Balance, & Sleep Patterns.... still not sure how meaningful any of this is.- Sleep Score details (see attached pic): there's a different detailed view of your sleep score; you get sub-scores for Time Asleep, Deep and REM, and Restoration, but I believe all the graphs are the same for non-premium users, so I'm not sure that this offers much more insight that the non-premium view does; I suppose you get to see how much each sub-score accounts for the overall score.- Instructional stuff: There are various workout routines, guided meditations, food programs, & sleep programs you can look up & do.- Games & Challenges: You can participate in various fitness games/challenges, which might motivate you to work out more.Overall, I think the Charge 5 is a nice upgrade from my beloved Charge 3, and for me, it was worth paying the extra bucks.