As far as these things go, it was fair. Nothing particularly offensive (although the overuse of "Doctor WHOOOO?!" has been mentioned, and it is now beyond stupid) although literally everything in this was just explained away with no consequences and no explanations - stuff just happens because.
The whole thing did just kind of stop, rather than have any sort of ending, didn't it? And we never did find out how Doctor Simian became so rich powerful – I'd been thinking the Great Intelligence pulled strings for him, but that assumption fell flat once it was revealed that the voice was just Simian's reflection, and the whole deal fizzled out. Ah well. It otherwise felt in keeping with "A Christmas Invasion," which is still my favorite of the specials, in that it was all about starting a new status quo and setting the Doctor off on his next season's adventures. So that was nice. Otherwise it was filled with the standard Moffat tomfoolerly, which is fun in small doses but is wearing a bit thin after three straight season of it.
The new console room looked better in action than it did in the promo pic, but I still don't like it that much. It's at its best when all the lights and doohickys are going crazy, but that apparently happens only when the TARDIS is dematerializing. The rest of the time, they relied on tight camera angles, keeping the background out of focus and filling the set with smoke (!) to make it look decent. I can only hope they'll refine the set over the course of the season and add more detail. Doing something to break up those staircases and the floor would do wonders.
That said, the show finally gave me the shot I've wanted to see for years now – the lovely tracking shot following the Doctor and Clara as they enter the TARDIS. It was even a wobbly hand-held camera at eye-level, for the "you-are-there" feel, which was how I'd always pictured it should be done. Very nice!