I've only had it since Friday, but my first impression of the brand new 15" MacBook Pro is all positive! This is a laptop that finally has the right horsepower combined with the right graphics cards. I can now run lots of applications simultaneously, including a virtual machine, and not have the fan kick on. That noise made my old MacBook sound like an auxiliary power unit on an airplane. The same good news is also true for watching Flash files: the computer handles them beautifully without any strain on the graphics card and no fan noise. I installed Vista Ultimate in Boot Camp to see how it would run, and it is blazingly fast. In short, performance is as good as I've ever seen on a MacBook, approaching the iMac. Lastly, the LED display is beautiful and the construction, fit and finish set a new standard for excellence.
More to come after I've had a chance to play with it for a couple weeks, but my initial opinion? This was one upgrade that was worth it!