Just ran my battery down for a spell after the update to Panther. I had been running the 10.2.8 version very well on a new PB 15 1.25.
Some people had been reporting improvements. I saw the exact same performance for the one battery "run" I've been able to do.
Don't expect anything different. Two and half hours seems to be the norm for Jag and Panther for me.
I am using airport on with bluetooth off.
Email and mostly browsing.