I purchased a LifeSpan Walking desk almost 4 years ago. I use it every day I am home. I have learned many things over the years but fundamentally it all boils down to this:
Get busy living. Or Get busy dying.
I work in a tech job from home. Which means I normally sit the full day and then some. I decided I wanted to up my activity level and the best way to do that was not only a standing desk but a treadmill desk.
Lots of studies show that standing is better than sitting. Lots of studies show dubious benefits of treadmill desks. Those studies all show the same thing. Treadmill desks are good but not sure how exactly. LOL. Sounds like science in action.
The reason I am writing this is because I have decided to replace my desk but keep my treadmill. The new desk is a Jarvis by Fully (nee Ergo Depot). Until the end of June you can get 10% off with the coupon code LiveSummer. Here is a review from the NYT http://thewirecutter.com/reviews/best-standing-desk/
If you have ever though of jumping into the standing business.. this is a great desk and a nice discount.
I have a lot more detail on this topic and would be happy to share it. One thing that I do find interesting. The treadmill only goes up to 4mph. However, I spend most of my time at about 2mph. Listening to calls at 3.2 mph. Talking on calls about 1.4 mph. Writing at about 1mph. And being super focused on my couch.