I don't see anything wrong with Christian Rock as long as it is understandable and gives glory to God. However, I figure if I can't understand what the words to the song or get any message out it it at all, then I can't say I'd consider it Christian Rock. For me, I'd rather not hear it in church. However, I tend to be more old fashioned to what is brought into church, because I was raised on hymns. To some of the more modern churches it may be fine. The Bible does say make a joyful noise unto the Lord. It does not say a beautiful noise, but if the music is glorifying to God, I do not find it wrong.
Boy is this an old topic ~ however, I agree with Music4Him. I don't want to hear it in my church but if the lyrics are praising God and the music is reaching the younger generation I say "Rock On"
Blessings~
TalkerCat