My office adopted these (for those who wanted them) about a year ago and has been great about letting us try different types. I've tried 3 and have been really aggravated by how inflexible/non-ergonomic they seem to be, i.e., I can move up and down easily but cannot adjust the position of the keyboard relative to the monitor, or get as close to the monitor as I want to be, with the two sit/stand systems I tried.
I now have an electric raise-whole-desk-up-down system that is great (same flexibility on positioning of the various parts whether it is up, or down), but annoying because unlike the other systems it takes -- I have timed it -- a whopping 15 seconds to move up, or down. That's a stupidly small amount of time to find as annoying as I do, but I do. I will say, I like to stand up for a bit (maybe 5 or 10 minutes an hour) but not for long. So that's part of my problem, i.e., my preference would be to go up and down a bunch.
I stand on a stepper, which I like for the flexibility it offers (but it is another part to need to move in/out as I adjust how I'm positioned), but it only works with the raise-the-whole-desk system (of the 3 I've tried); the other 2 didn't go high enough. Oh, and everything but the desk has been (way) too wobbly when I typed on it, i.e., whole system sort of wiggling/vibrating around as my fingers tapped the keyboards.
Long story short, I like the idea but think the purchased equipment leaves much to be desired, particularly considering what it costs. The DIY option (which I have not pursued) may make good sense in this setting (among others).