I have been using my treadmill desk for about 2 weeks (Feb 2013). I purchased the 2013 model with the bluetooth capability. So far I really like it, I previously used the treadmills at the gym but I found myself getting frustrated thinking of everything I needed to do. Now I can get as much exercise as I want while doing other things.
The desk is very stable, although not perfectly still (I have a large flat screen TV on a shelf sitting on top of the desktop and it shakes a tiny bit when I am walking. Most of the time I use it at 1.5 or 2 mph and it is very quiet at these speeds. When I walk at 3 mph though, there seem to be more noises (sqeaks, etc. not just an increase in the hum present at the lower speeds). Overall though it seems to be solidly built.
The biggest problem I have is with the bluetooth functionality, treadmill desk app and LifeSpan Fitness Club. I purchased a bluetooth adapter for my computer so that it could communicate with the treadmill and to be honest I am very disappointed. First the instructions for how to make this work are almost non-existent. To use this feature you need to register for a LifeSpan Fitness Club account (you get a 4 month trial free with purchase of the treadmill desk) and once you are logged in, download the treadmill app. Once you have installed the treadmill app, start it and press the Bluetooth button on the treadmill to connect the treadmill to your computer. The app will then display your stats from the treadmill (which the display on the treadmill is already doing). The only thing this app can really do is transmit the numbers to your LifeSpan Fitness Club account- if you don't sync the app with your fitness club account (which transfers the data), it will lose the data the next time you connect to the treadmill after resetting the treadmill counters. Unfortunately the transfer from the app to the Fitness Club is not very reliable. The calories and distance are usually correct but I have found the number of steps to be off and the time seems to be a completely random number (I must be a superhero to be able to walk 8 miles in 40 seconds). Recently I synced the app with my account after midnight so the data were entered for the following day. When I tried to sync the following evening (technically the same day as the prior sync) it never transfered the data so I had to enter it manually in the Fitness Club account. While you can edit the data that you enter manually, you cannot edit the synced data- so even though I knew the actual times, I could not correct them or change the day for the data uploaded after midnight. The treadmill app does have some historical data on it (displayed as a bar chart) but it is only for one week and apparently it gets this data from your LifeSpan Fitness Club account because even though the original numbers shown on the app were correct, the historical numbers are the incorrect ones.
Basically if you don't purchase a LifeSpan Fitness Club membership after your 4 month trial ends, the bluetooth feature is totally worthless. Since the data transfer is inaccurate/unreliable and there is no way to manually fix it, even if you have a membership it is not worth much at this point. It is safer to just manually enter the data and if you have to manually enter it anyway, there are a number of websites that will track your progress for free. However, if you are someone who will use the other features, like the exercise library, you may find the fitness club to be more useful.
To be honest, I was expecting this feature to automatically load and store my daily data in a stand-alone program on my computer (a program that I expected to be included with the treadmill purchase). I am also not happy with all the personal information that was required to open an account so that I could get the treadmill app, only to discover it was not very useful. Why do they need my exact date of birth, name, address, phone number, email, sex, height and weight just to enroll in the fitness club?
Overall, I really like the treadmill desk but I'm not sure the bluetooth feature and treadmill app really provide any additional benefit. Whether the fitness club is valuable or not depends on the individual and how much they will use it's various features. It appears that the fitness club website is still under development so it may become more useful over time.
***Warning: Read the warranty section of your user manual. It states that the warranty is only valid if you REGISTER the product within 30 days of PURCHASE.***