it only started as a test, but now i use windows 8.1 as my daily driver, its has a really responsive UI, stable as a rock , the start button is very welcome and i like the fact that it is customizable, at least there's an option to disable the annoying start scree&tiles. All in all, windows 8.1 is a good and stable OS, i recommend you do the upgrade. I came from windows 7, and did a clean install,..don't know much about upgrading though.