For the simple uses, XBMC is fairly intuitive - on pretty much any platform. That said it is very flexible, and can be adapted to most needs. This is where "complications" and hard work come in. It works fairly well out of the box, and the setups are fairly newbie friendly. The XBMC Wiki's are a haven of guides, pointers and other resources.
OpenELEC is a small Linux distro, designed for XBMC Media Center use. NUCs (Intel's "Next Unit of Computing") are tiny, fullworth computers. While the higher end NUCs pack some saucy price tags, the recent Celeron NUCs (like DN2820FYKH ) are about ~$120. They're not much for photoshop, but I have one of these and it performs much better than my i3 ultrabook. All else you need is a sata drive and a some RAM. If you choose to go with OpenELEC, you can even run it off a USB memory stick, and skip the internal storage (although I would reccommend a small SSD).
Personally I have 4GB RAM and a cheap 120GB SSD. Full cost, about $220. It is easily 2x the price of these android boxes... but it is also a fullworthy computer. Mine runs windows 8.1 pro - and while I mostly use it for XBMC - this also serves well for Netflix, UPnP Media server (using XBMCs library), utorrent server, small webserver.. and general web browsing etc. It can do anything other computers can do.
And when I want, I can use my Android tablet as a very intuitive and fully configurable toucscreen remote for XBMC on my NUC.
http://forum.xbmc.org/showthread.php?tid=117885
All along, my own intentions for media center was an Minix NEO X7 when they came out. You have no idea how glad I am, that I ended up with a "computer" instead (or, well... maybe you do). Those extra ~$70 was well spent. You get what you pay for, they say. Well - my personal experience, is that with this NUC, I got way more than expected.
