Windows 8 is a operating system by Microsoft through which it has tried to make a staunch return to the market which has now turned more towards apps.
The windows 8 UI is best enjoyed with a tablet or touch pcs where you can get the feeling of using your cell phone. This is the first time windows have taken a different form than the usual desktop design. The OS is very stable but few of the legacy apps are not supported by it.
But you will never feel any shortcomings in that regard and a lot of apps are available. The operating system is quiet stable and I have not faced any issue since last 12 months. For new users it may prove a little difficult in the start to get accustomed to.