I use my bluetooth headset daily and I have seen a few wonky bugs in this.
Occasionally I'll have to restart bluetooth to have it re-connect properly. Sometimes the phone fails to restart the bluetooth modem and I have to manually reboot.
Notification sounds ONLY go through my headset when connect, not out the phone.
So far I've had to reboot the phone or my bluetooth headset a few times per day. I haven't yet tried out an AOSP 4.2 rom that doesn't have some sort of bluetooth issues.
I use a bluetooth set of headphones and they have not given me an issue yet. I use Google Voice, so my texts and voice mail go through there. Sending texts I've not had much luck with even in Stock it got iffy sometimes. So hard to tell if it's 4.2 related. Since I've been using Google Voice my normal text messaging app has never been successful at working.