I was pretty happy with the episode, it was way from perfect (but then, I bet that is hard to define for all tastes anyhow - and even harder to acchieve
). I did like the ending, unfortunately I saw the hinting picture in this thread, so I was not speechless as I might have been without the hint, but I am not moaning! I actually liked AIISAT a lot, so that helped - he may not look that much like the real thing, but I think that is pretty close to getting the wanted effect... And the built up suspense towards the end and in direction of the Chrismas episode was really good, I dare not look at the calender to see how long we must wait, but the temperatures outside hint me that it is a freaking long time!
I thought the way they "ended" Bill was well done too, reminded me a bit how they "ended" Rose...
As for the Master(s)
Now the not so parts: The action looked a bit too much for a little too little budget ...
That's my take...