Hello, all. Posted this in the 650 forum, but it really belongs here.
Had my 650 for about a month now. I got a Scala 500 bluetooth headset with it. It was good, but not great. After much research and review-reading, ordered the HBH-662. It arrived this afternoon. Although I've only been using it for an hour, I'm impressed.

Pairing was too easy. Charged it, turned it on, turned on the Treo's bluetooth and just followed the screen prompts on the Treo. Have made and received a few calls with no volume or static problems on either end. I've left the Treo on the desk in the far corner of my living room and walked to the front door of the house, about 20 ft away, with no clarity problems. Couldn't do that with the Scala. The fit to my ear took a little getting used to with the fairly rigid earhook, but by rotating the entire unit once it's on, I've got it lined up well with my ear canal. And the fit is snug, even before rotating it. I don't have that feeling like it may fall off if I'm moving or turning quickly, like I did with the Scala. The only drawback is contact names aren't showing up, just numbers. After a few minutes' net research, this seems to be a drawback of the Treo, not the headset. Maybe someone will come up with a fix/hack? Anyway, maybe someone will find this info helpful.