I've had one for a couple weeks. Employees aren't flashing it around because it's basically not being sold anymore. I was able to order one when they briefly offered it online on a day in mid-November, proceeded to run out of stock again in roughly 10-15 min. Maybe a week or two ago, received an email from Microsoft that it will no longer be available online though you might find some stock in stores. My impressions from talking to a Microsoft store employee was that this version of the Band was almost a beta test product, that there wouldn't be many sold. My guess is they were testing the waters but aren't ready to go full in on a product that will compete with the Apple Watch in a few months.
I generally like it. I got it primarily for the fitness elements and it has some pretty cool features (always on HR monitor, step tracking, UV sensor and GPS). I've previously used a Fitbit Force and Garmin Vivosmart and while this is the bulkiest, it's been my favorite. I've been averaging a bit better than the advertised 2 days of battery life (closer to 3 for me) and like the touch screen/button combo vs. the button only on the Fitbit and erratic touch interface on the Vivosmart. Notification work alright but they're not synced with the device, meaning if I check a notification on the Band, it doesn't clear it as viewed on my iPhone, and vice-versa--may certainly be different if used with a Windows Phone. It also suffers from occasional difficulty reconnecting via BT LE after I've moved out of range (LE is used for notifications). Doesn't happen too often but still is a nuisance when it does--I manually force it to reconnect and then proceed to get a big backlog of notifications.
The fitness functionality works well. I've tracked long walks or runs using the GPS and it was pretty accurate. Heart rate monitor works fairly well. It isn't as effective as dedicated chest monitors but was fairly close to what I got manually checking. Because the band is designed to be worn a bit snug, probably helps with the heart rate sensor. One little feature that I also like is that you can add your Starbuck card to it--very handy to be able to press the Starbuck button and have then just scan your wrist.
Biggest cons are:
1) Size - on the thick size and similar to the Samsung Gear Fit, its orientation makes it more difficult to read the display without contorting your wrist a bit. I actually wear it with the touchscreen on the inside of my wrist--seems to help heart rate sensor and is easier to quickly glance at it.
2) Missing some functionality if you don't pair with a Windows Phone (i.e. Cortana)
3) Microsoft Health app is a bit limited and doesn't feed into Apple Health at this point.
4) Previously mentioned slightly sporadic connectivity issues.
Overall, my favorite all around fitness band so far.
