I changed from thottbot to wowhead as my main quest guide a few years ago because I thought it had better comments and advice and I liked the interface better. However, over the last year I have found the quest comments frustrating. I use them mainly for information on where the quest is located and any tips on doing the quest. I now often have a hard time finding that kind of information. The comments are mostly on what movie a line in the quest came from or what was meant by that line.
Despite not appreciating all the side-bar comments, I am glad for wowhead and it is still my number one source for quest data.