That was fun. I felt like they should have hidden the villain thing for just a moment longer - the audience almost basically knew the he memorized eveyrthing from almost the first scene, and the cafe scene with sherlock basically cemented that and basically for the audience that knew it was like... he doesn't need this paper database. It'd be too much of an ass/waste of time to CONSTANTLY write down what he knew, and beyond that, we knew he had 'good memory'.
Outside of that it was p awesome. We're reminded of exactly how falliable Sherlock is, from the very first scene with him to his loss against magnusson. Kind of a waste to not just let mary kill him when she had a chance.
AND OH GEEZ moriarty. That was fun, although how they go about it will be interesting. It's either a complex system he set up for after his death (doubt it, kinda boring), or he did survive (which would be like .__0).