The first unit I got had a defective microphone; I had to send it back; Jaybird replaced it; the new unit works, no problem. And it's very good. Good enough that I've been doing most of my listening on it for the past months. I've got better-sounding IEMs (the 4.A is the best I own), but the Bluebuds X offers the best combination of good sound and practicality, which matters a lot since I do most of my listening in the street, in public transportations, and at the gym. And yes, it has survived the sweat test. Actually, it's been surviving the sweat test on a nearly daily basis for the past month or so, since I've hit the gym regularly and it's so darn hot and humid here.
Bottom line: In my opinion, it's worth the asking price.
Did you buy direct from jaybird? Who handled the warranty?