Windows 8 is okay if it comes with your computer but I can't find any compelling reasons to upgrade to it from Windows 7. It's got that new replacement to the start button, the live tiles which is an interface that looks a bit like a tablet, so it's more designed for touching. I only have a plain laptop without a touchscreen so the whole metro interface of live tiles feels sort of like a gimmick to me.
Windows 8 is not really that great of a system. They do have touch, but because of this they have simply become too touch oriented. I would agree that the Surface tablet is a superior tablet, and if you are going in for a windows 8 device, I would definitely suggest picking the surface tablet. I, though, would not suggest upgrading to windows 8 in general.