I must admit, when I saw the trailer, I was afraid that Davies had introduced a shitty new Doctor as a parting blow just to ruin Steven Moffat's day, so I was very pleased with the resolution to that mystery when I figured it out well in advance of the reveal. At least, I figured out that he wasn't the real Doctor. Obviously the whole bit with the Cybermen having left their Doctor database on a USB stick on the train I didn't see in advance. I liked that bit. It nicely fit in: the TARDIS lands in the middle of an apparent battle between Cybermen and Doctor and the whole thing is explained by one event.
It was perhaps a shame that the Cybermen, a fairly interesting 'viral' villain like zombies or the Borg, were reduced to rampaging vandals, but they were probably necessary for the Next Doctor puzzle to work. I have no idea what the weird copper Cyber-ring-wraiths were in aid of, though. They were neither needed nor properly explained. I would have preferred they were left out, and that the Blink reference had stayed at the one line from Morrissey, but the episode was great with or without those things. I did like the "I can't not pull from this position" line.
Of course, the fact that I know Davies can produce such tight, clever plots makes it all the more infuriating when he doesn't, but that doesn't diminish my enjoyment of the ones he does write.