Last month I posted my first week experiences on my treadmill desk: http://squaredi.blogspot.com/2014/09/treadmill-desk-as-software-developer.html
Now I'll be moving into my one month review.
My metrics are:
Steps: 19.3K / day avg (darn weekends killing my average :) )
Distance: 11 miles /day avg
Max steps / distance: 31K / 14 miles
So far I've lost 5 lbs. I'm stretching every night. I'm still taking breaks as needed, but overall I'm taking standing breaks instead of sitting breaks. I have to have some foresight into the evening plans though. If there is a kids soccer game where I'll be helping run around, or a dance lesson that I'm teaching, I will need to stop walking early afternoon and sit so that my legs are capable of the evening activities.
I've noticed an increase in my endurance, where I've gotten 30K steps in a day a couple of times now and not been sore. I was also able to run the length of our street. (Note, I'm not particularly fond of running, but I was late for pickup from school. I was happy that I made it the whole street length, which is longer than I've run in recent past).
Given that I'm farther from the ground in the office, both with standing, and with the small step up onto the treadmill, that fans alone don't cut it. I've had to lower the A/C to help keep the room comfortable.
But the bottom line is that I'm loving it. I love being able to walk this much everyday and that it is not something "extra". I love that I can walk and work at the same time. I love that for a having a desk job, and working from home, that I'm lightly active to fairly active 6-8 hrs a day.