Loved it! So much better than the lame fanwanks we got every season of the reboot up until this season.
I thought it was a pretty good use of time travel, too... which is shockingly rare in a show about time travel.

I did notice three problems, though, and only one of them can be written off as an "alternate universe" version.
1. Amy shouldn't have been able to touch Amelia without BadThings(tm) happening.
2. Ditto for the Doctor touching himself. (Hmm, could have phrased that better...)
3. When the Doctor snatched a pamphlet to write the message to Amy, he snagged a new one from the present rather than reusing the one he originally gave Amelia. Since that results in a loop, he'd eventually run out of pamphlets and would have to start recycling, which he didn't do, which mean he didn't, even though he'd eventually have to despite not needing to, which results in a pretty big paradox. Hell, just typing that made me head explode.