Hi
Well its a lot to get into but I'll try keep it short.
Windows 8 is a def improvement over windows 7, hardware gets utilized in a smarter more efficient manner. It uses less memory than windows 7 despite feeling like its got a million and 1 things running in the back ground.
As far as gaming is concerned, I have spent a good month now with Windows 8..Load times for games like Battlefield 3 are much improved even if you're not running a SSD. the game def starts faster and maps load a lot faster, so there is def improvement there.
Hardware compatibility...Well haven't found anything that isn't compatible with Windows 8 which is a big plus but then again I only ever use the latest tech available.
Over all Windows 8 is awesome if you're into the whole "apple revolution" I feel like Microsoft is trying to copy apple with the layout and the ui..and to be honest its working..I've had tons of orders for windows 8...a lot more than I had with windows 7...It seems to be very popular.