The UI changes are for sure to give a novelty factor, certain user's get excited by it.
There is of course under the hood changes and the shift to making it a data hoarding service.
I am only just now changing my network and some family machines to windows 8.1 from windows 7. Windows 10 had me excited for it initially, up until the point it released where forced updates was confirmed and all the tracking junk occurring. But for me the biggest put off with win10 currently is its unstable state, microsoft have now copied google and moved to a rapid development model which is not the type of product shift I like.