My i760 arrived 2 nights ago (so I don't have extensive experience with it), but I have it paired with both my Infiniti M35x and an old Moto HS820 (I think) earset.

The i760 links to my car just fine, and disconnects when I shut off the car. When I put on my earset, it links up fine, too, and disconnects cleanly when I power it down. When I get back in the car, the phone links just fine again.

Last night, I ran the earset and car link/unlink cycle 5 or 6 times to see if it would fail, and it worked every time. The test was a bit artificial, though, since I didn't place any calls during it; all I did was turn each unit (the car or the earset) on/off to see if they would re-connect appropriately. But I watched the Bluetooth connection status screen as I did it, and could watch as it updated correctly.

Am I missing something?

By the way... my i760 is still pretty much virgin: the only software I've
installed is Epocrates and a couple of Sudoku games I'm using on a trial basis; no hacks or mods, though.