Hej,
I am using the Logitech BT headset. I really like it, but have one or two issues with it. First, the multi purpose button is horribly placed. I accidently click it when I put the headset on, and take it off. Sometimes this causes me to lose my connection, and other fun things. Second, I wish there was a easy way to turn the headset off. It can be turned off, but you have to hold the button for a long time, and do the same when you want to turn it on. there have been many times my phone rings, and I can hear anybody because I can't find my headset 🙂 (it would really be cool if they designed the headset to go on/off with the swivel of the microphone).
My friend has the Jabbra (new one), and a motorola one, and he likes both of them.
Kimo