I had a first generation Jabra that I had bought with my previous Sony phone and the sound quality was horrendous--I could hardly understand people when on the phone. I quickly stopped using it and I had spent a good $80 on it.
I just ordered a Motorola HS850 that should arrive any day now. I pray that it has better audio quality or I'm just going to give up and use the corded version which works well!
To be honest I'm mostly buying bluetooth because it is cool, not because I need to be farther from my phone than a cord would permit.