Mostly USB support and some visual enhancements (32-bit icons, gradient titlebars). Setting Tahoma as the system font would be nice too. I don't use NT4 anymore but it was my main OS several years ago. Fast as hell for sure. Those are just cosmetics I'd expect some more 'serious' cons against NT4 than that Ie lack of DX beyond DX5, lack of drivers for newer hardware, etc etc... Other than that its just great OS, perhaps one of the best to come out from Redmond (or should I say from IBM ) Actually worse, it only supports DirectX 3!