I bought the K&M stand with place for two keyboards a few years ago, and have since added an extension for a laptop computer.
First: what a relief not to have to get your knees into the X-shape of an X-shaped stand. The stand is solid but rocks a little, especially with a lot of weight on top, hammering on the keys, and having the stand in a high/standing position (which is the way I use it mostly).
I have used it both for sitting and standing positions. Changing the height is straightforward and the most cumbersome part is removing the keyboards (and cables).
Solid, good quality in joints and bolts, can be adapted to new configurations as needed.