I'm not sure quite what I was expecting from this one, but whatever it was, this probably wasn't quite it. I did enjoy it, though. There were two things that were bugging me as I watched: 1) It seemed way too easy, given the viewer's external knowledge of the show, to tell which of these two scenarios was real, which did seem to rob the episode of much of its suspense, and 2) It seemed to be setting up a false dichotomy between fun adventures with the Doctor and an incredibly dull and unfulfilled existence on Earth, which I really disliked. The ending neatly invalidated both objections, though, and I'm genuinely quite impressed with the way that it managed to fool me with what was, let's face it, not a particularly new and original plot twist. I'm going to have to watch it again in order to mull over the implications of what the Doctor's subconscious was telling him, Amy, and us. I'm really quite curious as to whether I'm ultimately going to end up feeling satisfied with that, characterization-wise, or not. I can, however, say once again that I am quite happy that the show is taking a very different approach to the Doctor's emotional psychology these days. The angst is clearly still there, but Eleven's reactions to it are the exact opposite of Ten's Sad'n'Lonely Emo Tears, and much as I appreciate Tennant's ability to convey vulnerability and heartbreak, I do think the Emo Tears approach had been taken about as far as it could go. This sort of sci-fi metaphor approach to externalizing the Doctor's psyche is an interesting alternative. I also really like Eleven's... functionality. He neither denies any of the painful stuff nor wallows in it; he just acknowledges it and moves on. It's reassuring, somehow. It's also a state I was fully expecting the Doctor to reach, sooner or later.
Also: Amy is still crazy, and I still love her. Rory, I am liking a little more each episode, which is of the good. And I may have said this before, but I love, love, love the fact that Matt Smith, young as he is, is playing the Doctor as decidedly old, and is doing an incredibly convincing job of it, too. And I like the fact that the writing is reinforcing that. We get a couple of references in this ep to the Doctor being old, and I loved him suggesting in "Vampires of Venice" that Amy pose as his daughter. It really highlights the idea of him as a very young-looking man with a very old self-image.
And I'll just add that I'm very glad, if we had to explore this territory at all, that the show, and Amy herself, have come out very firmly on the side of Amy/Rory, as opposed to giving us Yet Another Chapter in the Unrequited Companion Doctor Love Show.