Mixed feelings on the updates, but Microsoft seems quick to patch security vulnerabilities lately. Same topic but unrelated, W7 will fetch and download drivers that it doesn't have installed.

I find OS X to be too monochromatic - I've made several modifications to get bolder icons, Dock, white text on black menubar. Granted, W7 does lack the same tightly controlled consistency as OS X, but I like the look.

I'm impressed with the Ribbon interface. The point about the large bezels - they make them stand out; it's a good design idea for Windows (note the distinction - it's good within their UI paradigm).

ed: clarity