Well i have a first gen 15" uMBP base model. I have had 2 and they were both the same. First off my dad's friend brought over his new base model 15" uMBP with the SD card slot. Things i noticed: - Weight -- Noticeably heaver (Maybe they made the bottom thicker because they did away with that support bar that ran accross where the old door use to latch?) - Screen brightness -- increased color gambit, i dont think so looked exactly the same, except the new screen is much less "instant on" when the back light comes on it sort of turns on with a gradient where mine just "bink and it is on" - Sound (The bass and overall sound.. even the start up gong noise is much better on the new model) ... sorry for this ugly looking post but i just thought i would post the comparison.