Being on my first unibody, since my Early'08 MBP fried its board last Dec., was taken aback on learning the new "lifetime" of 1000 cycles w/85% capacity. Especially since the old removables had a lifetime of around 300 cycles/3-4 years and no earthshaking battery technology announcement has appeared in the trade journals to justify a 300% increase. Since my current, Late'11, practically comes hardwired for the Fat Cat, didn't even try how it would fare with the previous feline.
However, being that it is a full 64-bit OS, I can envision at least one or two paths to greater energy consumption. With the stock 4GB default RAM config., I've watched free RAM go down to zero and paging to spike with relatively modest use, as seen in Activity Monitor. Hence, full power consumption from both RAM banks and increased disk I/O in the paging areas. With an 8GB RAM upgrade, disk I/O should subside, but I don't know the power specs for the bigger sticks.
Another thing that I've watched thanks to the gfxCardStatus utility suggested here is frequent and gratuitious GPU switching from the most mundane of apps that certainly don't require the oomph of the Radeon. And that does cause a hit on the battery, cause it is one hungry chip. Battery Health is one of those switcheroo apps.