I have Nokia BH-900 that is BT 2.0.
So far the only difference I have noticed is the faster connection time to the phone.
With my older headsets (Nokia HDW-3, HDW-4, SonyEricsson HBH-300) it took about 5-8secs to connect but with this one it's 2secs.
Dunno about the battery life. Nokia has promised up to 8hrs of talk time with this one and up to 180hrs stand by. I can't verify this since I usually end up recharging it every day. So far the longest time I've been on the phone non-stop has been 3hrs and had no problems.
There are no REAL improvements that I have noticed. Sound quality is moderate with this ear piece.
I had Sony Ericsson HBH-IV835 (also BT 2.0) and it connected in 2 secs to the phone, but I returned it for its poor sound quality and short range ('bout 5 meters).
...and so it begins...