I recently sold my powerbook so I could finance my MBP. The PB was the last g4 revision with the higher resolution. I picked up a 1.83ghz MPB from the Apple Store yesterday and here are some initial impressions compared to the PB. Please note that I am not a professional user so no benchmarks were run. Speed: The MBP feels all around snappier than the PB. It boots fast and opens applications very quickly Heat: The heat on the MBP is slightly warmer than that of the PB, when surfing the web, I can use the MBP comfortably on my lap but when watching a DVD, it can be a little uncomfortable. Also, the palmrest on the MPB is noticeably warmer than the PB. Screen Brightness: On the PB, I would have the brightness set to the highest level at all times. On the MPB, the brightness at the midpoint level is equal to the brightness of the PB at the max level. Battery: On the PB, at full charge, I would get a little over 3 hours of use. On the MBP, without calibration, I got about 3 1/2 hours with a full charge. Noise: My PB was absolutely silent at all times. The MBP, is very silent as well. My MBP has the high pitch whine that seems to be prevalent on these models but mine is barely noticeable. I have a lot of ambient noise in my house, so I cant really hear the whine unless my ear is right next to the MBP. Overall, I am very satisfied with my purchase. I was a little wary about getting the MBP because so many people were complaining about the heat and the noise, but those are non issues on my MBP.