All the threads on all the forums that I could find that contained info on the GT2 and GT3B have all said the same thing; they perform the same, but the GT3B has more options. So if you are satisfied with your GT2 (I am) then don't hesitate because your not going to find a better deal.

Is the GT2 your first and only Tx? If so you don't need opinions, you need to feel with your own hands the other expensive brands. My Airtronics Tx trigger and wheel both have nicer feel and weight to their movements, and the overall balance in hand is better. Performance wise, I'd be a liar if I said I could feel a difference in controling the car. So either I'm a hack or the performance is more than adequate. You'll see a way bigger difference in servo choice.

Yes the FlySky will get the job done, I am getting one soon (GT3B) to add to the GT2 I just got for my son. But the other radios not only get the job done, they do so with a substantially better feel.

Are you willing to pay a premium for steller performance and build quality?