Last year I started my journey using a wiki with my students. I set up the wiki using PBworks. It worked fine and I enjoyed using it. My district prefers that we use Wikispaces. So I have spent some time comparing the two. I like the clean organized look of Wikispaces. (point for Wikispaces) PBworks allows me to customize student username to actually be the students name...point for PBworks. There are slight differences in editing, but it takes only a short time to get used to how to navigate Wikispaces. The determining factor is going to come down to discussion forums. I am really looking for the ability to have a forum discussion on our novel studies. PBworks does not have this feature, and Wikispaces does. So, I think that I will venture out and use Wikispaces this year with my students. I will keep you posted along the way.