I was completely surprised at how well built this product was. It ships already assembled and ready to go. This product was larger than I expected, but it still managed to fit my work desk.
It's extremely easy when going between a sitting position and standing position. One concern I had was with the functionality of sitting the unit back down to a sitting position. I wasn't sure how much of my own strength was required to make the transition smooth, but it requires little to no effort on the users part. So you don't have to worry about items on the desk being disrupted when sitting the unit down and even when lifting the unit.
One tiny caveat that I have is the design of the top tier. I have a MacBook Pro and a Dell 24" monitor and since the top tier is "U" shaped, my macbook pro slightly hangs off in the front. It would have been nice if the top tier was shaped like a rectangle, but I'm sure it's designed that way to prevent heavier items being placed there and to prevent the unit from falling over.
The free software that is included (you have to download from their site) is pretty cool. It's very simplistic which is nice in some ways, but it would be really nice if it kept a log of everything and allowed you to see overviews in weeks, months, etc. of the calories burned.
All-in-all I would definitely purchase this product again. It has been a great investment!