I'd list everything I hated about this episode but I would basically be quoting the script, word for word.
The concept we saw in the trailer—Daleks apparently helping the Allies in WWII—felt fresh and interesting, and there were so many ways it could have been explored meaningfully. That would have been quite a treat considering almost every Dalek story in the new series has been thoroughly embarrassing (the exception is "Dalek"). I'm not sure, but I think this might be the worst Dalek story ever.
Seriously, almost every minute is a fresh letdown. Dismal storyline, dismal dialogue, unconvincing emotion, ghastly Churchill impression (at least I hope so). The whole episode is centered around an unintentionally hilarious Dalek redesign; they're painted in candy colors now and they have a vocal filter they stole from the Strokes. There's even a totally gratuitous Star Wars ripoff sequence, complete with "I can't shake him" moment and "shields down on the Death Star for one pilot to get through" moment, which is even worse when you find out it's happened because a Dalek android has, in about 40 seconds' time, retrofitted WWII fighter planes to fly through space.
There are exactly two bits I kind of liked. One is the moment when Amy teaches the Doctor that humanity is better defined by love than by pain, supported by admittedly excellent acting by the Dalek android (the only decent performance in the whole episode, unfortunately including Matt Smith and Karen Gillan). The other, though I saw it coming, is when the Doctor eats the cookie he's been pretending is a TARDIS self-destruct device.
No one on the new show has any idea how to write a worthwhile Dalek story. It was inevitable that they'd come back, and now I hate them just as much as the Doctor does. If the price of scripts as good as "The Ark in Space" is more monsters made from green bubble wrap, I'll pay it. Anything's better than seeing these Fiestaware salt shakers at the end of every season, but it seems we'll never be rid of the bastards. KBO, indeed.