It started out pretty random and meh, and I was pretty much just 'ho-hum, yet another sexy depiction of the Mad Hatter and a parent-child relationship and the Queen gets involved, w/e.' Also, I was quite disappointed that Mary Margaret used the key. What would be better proof of her character than turning the key in instead of using it? But, well. The Mad Hatter was actually portrayed as kind of psychotic. I mean, they showed us his reasons for it, more or less, but he still came off as dangerous and likely to snap at any moment rather than more of a goofy or tragic madness. At first I did not approve of the addition of Wonderland, but having it be one in a series of worlds that he was able to get to via the hat was interesting and unexpected. I also liked his speech on the subject, and felt that he had much better chemistry with Emma than August does. Regina was acting a little... differently, but I don't know exactly when those flashbacks tooks place, and I liked her going a-questing with someone she wasn't actively trying to attack or whatever (it struck me as similar to that time she was acting sorta friendly to Rumple during Skin Deep), and I liked her genuine emotions and sincerity upon freeing her father. I was delighted that Emma was just playing along and then Emma and Mary Margaret kicked Jefferson's ass. (Because, though I liked him by that point, he could've been planning to rape them for all she knew, and I was kind of despairing at the apparent plot-required sympathy). And I think it was super-interesting that Regina and Rumple made a new deal in the real world. I don't think they actually said what it was. Rumple could serve as Mary Margaret's lawyer if he left her cell key in the cell, maybe? Oh, and I loved the moment of emotional bonding stuff where Emma called Mary Margaret family and was almost in tears.
However, I think it's a shame that they wasted Wonderland in this one, B-plot episode, rather than exploring it properly in an arc or something. It didn't really translate very well to the small screen (the maze looked good, but the caterpillar and grass and mushrooms were just a world of meh, and the court was pretty bland, too. Really it needs a lot more nonsense than most tv/movie creators are willing to give it.), and there were some very obvious things influenced by the live-action movie (which I hated, so that was definitely a minus for me). Also, I know this is a world with riding habits and ball gowns and leather pants and impractical cloaks and sparkles, but I wish there had been an actual reason for Jefferson and his daughter dressing more Victorian than everyone else. Did they originally live in another world? Because if that's the case, they should have mentioned it because that would be fascinating!