if you have a USB/ehdd back up of [i][b]everything[/b][/i], do it. pretty much the only negative is that you get the built in "cortana" assistant to index your stuff on the cloud so people can search your pc. they say it can be turned off...but really? local storage isn't local any more. you get better security(couple of fatal kernel security flaws in 7/8.1 that can kill security, but are embeded in the kernel too deep to patch), better speed, DX12(not coming to 7/8 users) you also get an entirely new UI that combines windows 8.1's desktop mode with a start button menu that has a hybridized sort of metro ui layout. instead of switching tabs, you switch entire desktops. power users who memorize a lot of keyboard shortcuts will have a much better time. and yes, i very mad. first it was"you need media center to stream xnla music server to your xbone", then it was media center requires windows 8.1 pro("enterprise") and an additional upgrade. now they said if you have 8.1 enterprise (pro), you don't get a free upgrade. like WTF, no customer loyalty after all your hoop jumping bullshit, MS?