If you have read about the awesome Tribit Xfree Tune, this is the newest model from Tribit.
Amazon has them on sale for $24.99 w free shipping.
The main differences seems to be the head cups now swivel, the ear pads appear to be more like memory-foam, and overall a bit lighter. Battery seems less than the Tune (25hrs vs 40hrs) but charges faster via "quick charge". GO has BT 5 vs BT 4.1 for longer range as well.
I already own the Tune (I use them almost every day and are still working as well as day one) and found them to be the most comfortable headphones I owned (I have a Sony and JBL as well). As a bonus plus being able to listen via audio cord w the headphones turned off made it super convenient to me.
Here is a review comparing the Xfree Tune w the Xfree Go