First off, loved the episode. I haven't been fond of the "upgrades" made to some of the other Classic Who creatures in New Who, but Neil Gaiman did a bang-up job with the Cybermen. Logical developments on the part of the *real*" Cybermen (not the Cybus Industries machines). I also liked the acknowledgement of the Cybermats and the CyberTombs in the episode. I have to admit that during the Cyberman movement bits, I half expected to hear the sound effect for the bionic movement from The Six Million Dollar Man and The Bionic Woman. Fortunately, that didn't happen. Look forward to seeing the Cybermen again.
I was pleasantly surprised with the appearance of Warrick Davis in the role of "Porridge", and thought that Tamsin Outhwaite was also excellent as the Captain. The acting was pretty good for the most part, though Clara's child wards didn't really do much for me, and were pretty superfluous to the plot. As usual, Clara's story and the whole emphasis on Clara in this spring season of the show is annoying as heck, though she had a few good lines in this one. Matt Smith was quite good in the engaging with his inner demon, but both parts seemed to be a bit over-the-top to me, and I'm tired of that, too.
Neil Gaiman did a good bit of writing with this script, and brought the Classic Cybermen back in a way that made sense, and with a story that was fitting for them. Overall, a good story, and that makes two in a row following on from "The Crimson Horror".