I recently got a standing desk and quite enjoy it. They are definitely viral; once a few people get them in an office, everybody wants one.
I even wrote a set of Perl scripts to keep track of how much time I spend sitting vs. standing, and how it changes over time.
The only problem is that I don't know of any good studies on what stand / sit ratio is medically recommended. Too low and you get back and other muscle problems; too high and you get joint problems.
You shouldn't be getting joint problems standing around all day. If you are getting something like that, these issues might be arising from fatiguing of the muscles from having to support yourself standing all day. When your muscles are fatigued, you end up supporting yourself less with the muscle and more with the joint, so you get weird "wear" patterns, things misaligned slightly. For example, the front of the thigh pulls more on the thigh bone than the rear of the thigh. That can cause kneecap soreness (patellofemoral tracking gets all whack). Muscles in your core can fatigue, and they are also essential to maintaining correct posture.
The fix in that situation would be to work on basic leg and core strength. A set of ankle weights, straight leg raises, side leg raises, calf raises, some basic "good all around" core exercises (forget the crunches, think plank) can really help you avoid joint-related issues from standing all day.
FWIW I have both a standing desk and sciatica due to a bulging disc injury. My physician, chiropractor and physical therapist all agree that I should stand and walk as much as possible (all day at work is fine) because of the benefits for my back.
Mainly, they claim that I will spend a lot of time making small movements -- shifting weight from side to side, repositioning myself, etc. -- and these movements of my spine are beneficial. Evidently, these kinds of movements (and also a lot of walking) move the fluids and nutrients in the spinal cord that keep the intervertebral discs vital.
I even wrote a set of Perl scripts to keep track of how much time I spend sitting vs. standing, and how it changes over time.
The only problem is that I don't know of any good studies on what stand / sit ratio is medically recommended. Too low and you get back and other muscle problems; too high and you get joint problems.