Pretty darn good
Use primarily for workouts, this was an upgrade from my Jabra Pulse Wireless head set. Out of the box they are pretty much what any Jabra user would expect as far a comfort and ease of use. They secure into the ear and dont have much movement when I am running, jumping, pulling ect ect.
Sound quality is as expected. They are not Bose quality, but they are good quality and not tinny. In fact I might suggest the sound quality is better than my Jabra Pulse head phones..crisp and clear and not too much bass. The only issue I have is that there is a whistle from the wind when I am running. I have not solved that problem yet and I am wondering what it will be like if I am skating or riding my bike.
the firm ware is great and the Jabra App is pretty consistent and accurate regarding distant, heart rate and reps. Its a bit of a pain to edit a work out that is user built but its easy enough to redo it if needed. I do like the added "find my head set" feature.
The recharge is pretty effortless and I have not burned thru the battery of either the case or the unit yet.
With the first generation true wireless bud, these are darn good for the money. I would take a manufacture rebuild over an off the shelf purchase any time.