My battery life on my early 2011 17" MBP is around 6:00-6:30.
When I switched over to Lion, it was reduced to about 3-4 hours, but then I installed gfxstatus and always had my machine set to "Indiscrete Graphics" which bumped everything back up to normal battery hours.
so you're getting 6-6:30 hours on mountain lion?
Is 3-4 hours normal for my 13" 2009 MBP? I used to get ~7 hours with Leopard, it dropped slightly with Snow Leopard, now this.