Great resources if you want to look inside: http://blog.macsales.com/15913-a-peek-inside-the-imac-21 http://blog.macsales.com/15932-what-does-it-take-to-upgrade-a-2012-imac-21-5 Key points: 1) Display is kept on case by adhesive, but they were able to slice through the adhesive with a round pry tool (looks like a guitar pick). 2) SSD bay is only in higher end 21.5, but it uses the same sort of SSD blade as is in MBPr 3) The main drive is a standard 2.5" drive, but they haven't established whether there's any funky fan sensor issues as there were with the previous generation iMac. ---------- I should probably add a 4th: It's not obvious to me how easily the screen goes back on the case. Unfortunately, it's not held in place by magnets. I'm definitely not opening mine until braver souls answer that question.