The 7D II is more of a pro camera. Here's dpreview link:
http://www.dpreview.com/reviews/canon-eos-7d-mark-ii/18
the 550D is an enthusiast camera. Again. link to dpreview.
http://www.dpreview.com/reviews/CanonEOS550D/29
Hope that this helps and not make it more confusing.
BTW, I'm not a Canon man anymore, but I'd go with the 7D II.