On a whim I purchased a microsoft band - I figured if it wasn't great I could return it. What made it attractive was that the fitness functions (GPS, heart rate, steps, etc) work without your phone so you don't need to take your phone with you when you run. The Starbucks app was also huge for me, because it lets me get my post-run bagel and a drink without needing my wallet. The form factor (thin horizontal screen) also seems to makes more sense than the iWatch.
Here are my day 1 thoughts. Overall, it far exceeds expectations. Very intuitive, very well designed - feels like an apple device. I feel confident using it already.
Running - tracked my route, and showed me live heart rate, pace, and distance information. Much easier to see while running than Garmin. It buzzes every miles, and gives you a clear distance message. Lots of great info on my phone when I got home and it synced. One think I didn't like is that it had the same issue as Garmin watches of needing a few minutes to acquire the GPS signal at the start of the run - my phone seems to get it's signal much faster. Accuracy was about 10% off my buddy's Garmin - don't know which is right but as long as it is consistent like the Garmin I don't really care.
Sleeping - thought the sleep information was very interesting. In the morning I got a graph showing when I was in deep sleep, when I got up, resting HR, etc. Not sure it is very actionable, but still interesting.
Smartphone Connectivity - I didn't get a whole lot of benefit from getting email / phone alerts. Too many email alerts - I only want to hear about the most important emails - presumably this will get better. Notifications were completely useless (I want to be notified if there is a Zombie Apocalypse, not every time someone scores a basket on an obscure college basketball game) and I turned them off - again presumably this gets better. I did find the calendar useful for keeping me on time around the office. Weather was also unexpectedly useful. I generally checked my phone 50% less.
My FitBit is dead to me. The FitBit is basically a very expensive pedometer. I can't see myself every using the FitBit again. I think it also kills Garmin, this is everything their watch does without the need for the heart rate band, plus some extra smartphone functions.
I read a lot of buzz about smart software, that can generate insight from the data, but didn't experience any of that. It did do a good job of sharing data around. For example, the exercise data automatically logged the calories into MyFitnessPal (a diet/calorie tracking app). It also shared my run data with Run Keeper.
The form factor is perfect. I have small girlish wrists, and don't usually wear a watch and it never bothered me. Not much different from the Nike Fuel band. The display and touchscreen work smoothly. The band has a neat clasp that make it very easy to tighten (say when you are running) or loosen (the rest of the day).
Few quibbles. The battery seems like it is going to struggle to make it through a full day if you take it on a run (the GPS eats the battery). Otherwise, it seems like it makes it easily through the day.
I wonder how the band feels after a year of wearing it. It was brisk this morning, but in summer this is going to get covered in sweat. I hope it doesn't get nasty. But, at $200, I also wouldn't be upset if I had to replace it every year.
It doesn't seem very popular - the Microsoft store where I bought it had nobody looking at them, and the salesperson mentioned this was the first one he had set up (it was late at night). Not a spectacular launch. This makes me wonder if it gets a lot of third party support. If this was an Apple or to a lesser extent a Google product it would be a massive hit.
Overall, very impressed. This is what the iWatch should be. Wouldn't hesitate to recommend to a friend. My advise is to try one, you have 30 days to return it if it doesn't meet your needs.