Well, according to my MacBook, my battery life has actually increased 30-45 minutes. Granted, I haven't actually put a real timer to it, I'm just going by what the built in meter says. When I unplug the MacBook now, the meter says over 5 hours of life. It used to say 4 to 4 and a half hours.
Who knows if it went up or not, I don't really know...