That bit with the hairband was excellent. (As was the hermit crab TARDIS.) There's a good collection of quotes from the ep here: [link]
That line about being an excellent Doctor I felt was a bit off. It certainly fit this year's themes, but it was perhaps a bit heavy-handed. Plus, Clara had been good (conventionally speaking) in the role. Unlike Twelve, she didn't show any ruthlessness about gaining advantage from people about to die, she was clearly affected by 22's fate, she came across as concerned about the lives she was trying to protect, not just trying to win against the threat du jour.
(Twelve too seemed to have more room for compassion with less call on him to act. At the end, dealing with the odious Fenton, there was a contrast between Fenton's dismissal of the dead and the Doctor's accounting for them.)
The Doctor's statement to Clara could be construed as saying that competence rather than compassion is what made her so effective. (It would be interesting if he were to go so far as to claim that compassion would make the Doctor less effective, since he's argued this point repeatedly against Daleks, Cybermen et al.) But the delivery felt wrong for that, as it's not really something for which Clara needed to be chastened there.
On the other hand, there were points about which Clara could quite legitimately be pulled up, most obviously her breezy treatment of Danny. (For the record, I don't think the Doctor was as approving as he sounded about her talent for deception.) I think too that there's something in her being so concerned for the Doctor's approval that she ignored a call from Danny to press the point. (I don't know if the Doctor thought that was unseemly given that there'd been a death toll; I don't think he really has enough credibility to make an issue of it.)
Anyway, for all that I think that line was trying a bit too hard to be clever (and the Doctor had in fact previously said both that she was good and had made a fine Doctor), I liked how this episode broadened the emotional landscape of both leads. Clara's becoming more accepting of the Doctor's morality, and more practiced at emulating it; the Doctor, it seems to me, is starting to question it a bit, seeing it from the outside with Clara. (I think the last four episodes have all, in different ways, given the Doctor something to ponder.)