The biggest problem with this set is the price.
Seriously, the whole time I was buying it I just kept saying "sucker, sucker, sucker" in my mind... ack... the price of being a set collector.
It has several good pieces, as was mentioned... I love the guaridian and use him as my avatar - the stain glass pieces are nice, although I have many of these already.
The set is just too... incomplete. It is full of holes and not really any sort of Citadel, or any whole building. I remember sometime back someone did a great little remake story of the KK2 assualt, but with a much improved citadel - something between the great MOC they used and this set (full of overly-large pieces and holes) would be perfect.