I bought these in the Woot last month.
I have had no bluetooth problems at all when indoors, which is where I mostly use them.
When outdoors, the bluetooth can cut out from time to time, but I haven't used them outdoors much yet. Phone placement is critical. I also haven't really used the activity features, although the heart rate seemed accurate when I've checked it.
I've found them to be very comfortable and the sound is very good. Not great, but definitely very good.
I love the touch controls, the transparency mode and the charging case.
There's no way I'd pay $300-$350 for these, but for $100 I think they are great. I'm seriously considering purchasing a 2nd pair as a backup.