The only problems I've really had with JB are with bluetooth and the issue with wake mode. Both are known and Peter is working on them. For the most part, the button on my headset launches the Google siri thingie and not AVX, and the constant beep when in wake mode (JB listening for "Google") make wake mode pretty much unusable at this point.
Using AVX in general though has been pretty good. MUCH better overall than on my Droid X, which I upgraded from to my Razr Maxx HD.
You can always give it a try and if not happy, uninstall during the trial period. Wouldn't cost anything but a little time.
My big like with AVX is hands free texting and not having it go to another screen to review and send. It goes from start to send via voice...use it in the car a lot.