A truly non scientific test ... The '09 15" MBP C2D 2.8ghz, 512vram comparing to April/10 15" MBP i7, 512vram both have 4gb ram and 256ssd. The '09 allows the user to choose the graphic card setting but you have to log out first ... The new '10 MBP has 'auto switching' and decides what to do for you, (until Apple releases a fix, which many feel they won't do). In our experience the '09 MBP runs cool, noticeably cooler on your lap for example in integrated mode .... But when you switch to the discrete card then you can feel it's quite a lot warmer. Battery Meter - On full battery, switching from discrete to integrated mode adds 1 hour 41 minutes. With the new 2010 models choosing to run in discrete mode, even when seemingly unnecessary it makes the machine feel much warmer on the bottom almost uncomfortable. That was noticed in the '09 MBP too when only when running in discrete mode, but when running in integrated it runs very cool. Battery life is about the same on both machines, Apple advertises it increased over the '09 models, in our real world experience not the case. This first step into Intel Graphics and these being first version machines unless you really need to upgrade now I wouldn't ... If you have an '09 or an '08 MBP chances are it's doing it work just fine and you'll notice minimal improvements and perhaps take a step backward going from Nvidia graphics to this new Intel idea .... it's not perfected yet. Therefore unless you need/want to run in discrete mode often I'd wait until the next revision/update or at least until the graphics switching concerns are addressed by Apple.