Ok, so here is my so called solution to the BT problem with my H17.
Background: I have had 2 new iphone 4 (they replaced the first one for me).
I have tried 2 brand new Motorola H17 and a Jawbone Noise Assassin (new in summer of 2009).
Problem: I can hear loud and clear, but reports from other end is very muffled, sound like I'm far away in a tunnel, can't understand anything you're saying, etc.
I tried resetting network, resetting settings, etc...
Sometimes it would work great and people said wow you sounds great. Sometimes report the opposite as listed above.
Here's the deal:
If I start the call - either initiate the call, or receive a call, with the BT on and connected to the phone, it sounds like ****.
If I start or receive a call while on the actual phone, and with the BT OFF - then, once the call has been connected, THEN turn on the BT and go to BT, everything is great.
I have tested this all day, and definitely, 100% of the time, I get the same results.
Would be really interesting if you guys experiencing problems could replicate these results...