My experience: I bought 2 pairs last year on Woot, they were refurb, and they worked well for a few months. Then they would not charge. I was able to return them to Motorola under the year warranty, and printing out my woot order page was sufficient for proof of purchase.
So, it's great that Motorola honored the warranty, because I had to return them a total of FOUR times (total, not each) before finally getting a pair that seems to be holding up. Each time it was the same "won't charge" issue.
As for the performance of these headphones, they're OK. I don't use them for general music listening; they're too uncomfortable and tinny-sounding for that. But for working out, they're great. I wish they could go a little louder, there are times when I'm at the gym and the ambient noise is louder than I can get my music. But for running outside, they're pretty good, as long as my iPhone and the headphones are both cranked up.
If you're considering these for working out, and primarily fro that purpose, they'll do, just remember you (should) have a year warranty when (if) they crap out. I can't recommend getting bluetooth headphones for working out enough, though. These or another pair, being cable-free while running or biking or lifting weights is very liberating. You won't want to go back to cabled headphones after you try it.