I'm a big fan of linux for servers but I'm still waiting for a distro with a UI good enough to replace windows. Linux mint is the best I've seen and it's getting better but it's not quite there yet. It lacks polish in a number of areas that still have me waiting for a future release.
The advent of the horrible windows 8 has made the need for a viable alternative more urgent. Eventually windows 7 will no longer be available and as windows 8 is a steaming pile of excrement and completely unusable as an OS, I (and I'm sure many others) will need to change to either linux or apple. I intend to change to linux and most likely linux mint but hopefully by then, further improvements to the UI will be in place.
Single most annoying item is the lack of a wait cursor when clicking on desktop shortcuts. There is no indication that anything is loading until it loads so you often end up opening multiple instances because you didn't think the first double click worked.
It is important that a wait cursor appear while waiting for an app to load. I have seen users go click crazy thinking nothing is happening.
It would seem to me a trivial item to fix and yet such an important part of the UI experience, I don't understand why this bug hasn't been fixed yet?