Honestly, I thought Dune was superb, Dune Messiah was dull and boring, but Children of Dune went back to the winning formula. I loved it!
It goes back into politics and corruption and everything. He took my favorite character (Alia), and successfully and believably made her evil. The brought back the evil Baron again, who is just as wicked as I remember through her. They gave the whole 'abomination fear' the Bene Geserits have real meaning.
The only thing I found a bit fruity was the 'sand trout stillsuite.' I may not read the next one, because I hear it gets a bit weird with Leto transforming slowy into whatever he is going to become and such. I have a few other books I want to read, but eventually I will go back and read the rest of the Dunes.
I just wanted to say I really enjoyed Children of Dune... about as much as I enjoyed the original Dune. So if anyone got bored with Dune Messiah, it is worth getting through so you can read Children.