New Bluetooth phone - Blackberry 7100t

You might try adjusting the bluetooth sound volume parameters as discussed in previous posts. Here is a recent one:

Bluetooth diagnostic screen

I had some voice quality problems after upgrading my Treo 650 and was able to improve it somewhat by decreasing the outgoing sound volume to -4.

 

I wanted to add additional information for those interested in the phone and a work-around for Bluetooth phone entry transfer.

The BlackBerry Unlimited Internet plan is $19.99 to add on to a voice plan. This has BlackBerry Web Client which has push e-mail (I actually prefer IMAP, but what can I do unless I want to pay through the nose for a PocketPC phone/service). Alternatively there is a $29.98 which adds BlackBerry Enterprise Server (BES) support which allows wireless synchronization of Personal Information Manager (PIM) if you have access to work/school/other BES.

I was able to use a laptop with a Kensington USB Bluetooth Adapter to transfer phone entries one at a time. I had to fiddle around a bit with the instructions here.