(This topic looks more like a poll to me, BTW)
A difficult decision, but I will have to go with Anndi McAfee's voice. Candace Hutson seemed to be the right kind of person to play a bratty girl triceratops at the time of the first movie, and it was nice to see her come back for the first few sequels, but, despite the fact that McAfee is a couple years older than Ms. Hutson, it still doesn't stop her from playing the character that is Cera at an incredible rate. However, Cera might indeed need to be re-cast if, by some crazy miracle, a new movie ends up in the works, but of course, the chances of that are unlikely.
Either way, though, I like both voices as well.