Mine has had BT lag issues. At least with my Jambox and my 903+ headphones. only things I've tested are BS player and ShadowGun Tegra 3. They both lagged significantly (1-2 seconds). playing a movie straight from the gallery however with the native video player, it seemed in sync.
So its possibly a processing issue (bells n whistles of BS player, and tegra 3 graphics with Shadow Gun). Still quite disappointing though. I figure Bluetooth has been around long enough. New devices, especially $500 devices, should be able to handle transmitting some BT audio in this day and age.
Perhaps Jelly Bean will magically fix something!
One can only hope.