I think this episode is the best complete story episode of the season. In all honestly, "Time of Angels" is probably the best episode, but I'm grading it in combination with "Flesh and Stone" which was a disappointment.
The gross romance between Amy and the Doctor have been resolved. Amy has realized how much Rory means to her (which was a bit sappy, but in a good way). It's nice to see Amy get over her clingy childish doctor fantasy.
It was absolutely wonderful to see the manifestation of the doctor's dark side. It really helps to flesh the doctor out. We've only caught glimpses of the angst/drama of DT in this season (ep 1 and 2) and it was nice to get a good chunk. My favorite line is "I know who you are, nobody else hates me as much as you do".
One thing though, am I the only one who found it odd that Amy married Rory and was about to have a baby with him but hadn't told him she loved him?
Pregnant Amy and Rory's ponytail was wonderful comedy in a very suspensful episode. It was a really nice balance.