I have not had any issues using the bluetooth on the phone either in my car or on my Big Jam Box.
I have had issues with NFC on occasion where it seems to have a hard time reading tags but nothing on the bluetooth side that i have noticed.
yeah i contacted htc about this phone and they said it's a known issue that they're trying to fix. the rep asked for all my phone info to help them figure out what it is. since then i've actually had to do a complete reset of the phone, hoping that'd work, but it didn't... i'm stuck listing to the radio or suffering with one track at a time :/
ok so now i'm just confused. m wife has a samsung galaxy s iii that connects no problem and i tested out an old pair of motorola s9's to my phone and they work with no problem. my last 2 htc phones, touchpro2 and thunderbolt worked no problem... so what's the problem?!?