I really enjoyed this episode. My initial reaction was that it was a bit too sedate, but upon reflection, it was a welcome respite after the action of the previous two-parter. Tony Curran was great as Vincent, and it was wonderful seeing Bill Nighy. I liked that Rory's absence (or rather nonexistence) was touched on here and there (such as the Doctor calling out "Amy, Rory" when he was going over what they were all going to do), and the visual nods to Hartnell & Troughton were nice. Even the monster, though CG, had an old-school puppety-costume feel to it. And the Doctor's rearview mirror gizmo seemed completely in tune with this Doctor.
I thought the scene where the three of them were looking up into the sky was wonderful, and in particular seeing how Vincent perceived the sight. I was also quite moved by the scene where he was in the modern-day gallery, though Nighy's character seemed to be doling out praise a little too thick, as though he knew somehow that it was really important to answer the Doctor's question very, very, very thoroughly. And the final scene was also very sweet.
Not looking forward to another pointless preemption next week and falling 4 weeks behind the UK. If people are away from home, they can bloody well tape it!! That's why they invented VCRs and such. It's so aggravating!