I agree that Conservapedia is opinionated and biased--just consider the name--but they are up front with it, so no surprise. There is some good information there, but the reader needs to filter it.

I have found several articles I would consider opinion in the past, but I would not consider Wiki to be biased. It is an open environment where much is posted without citation. Opinion and errors show up there, but can be corrected or amended by anyone registered. But the changes are not necessarily accurate either. This openness is both its strength and its weakness

I do use Wiki as a first-look place. If there are links, I'll follow them, or I'll Google or both.