Pros: flexibility; practically self-employment
Cons: no loyalty to tutors; no pre-screen of students
Think of Wyzant as a dating site - there are plenty of frogs among the princes. Also, Wyzant is no fairy godmother. (sorry about the mixed metaphors)
I was able to find a decent number of good students to tutor, but about 20-25% turned out to be irresponsible, or their parents were controlling and dishonest. In a couple cases the parents arbitrarily rescheduled or cancelled & then objected to the cancellation fee. Wyzant then sided with the parent despite clear policies to the contrary. I also had a parent second-guess my chemistry tutoring when she clearly had no idea what she was talking about.
Overall not that bad an experience, but be aware that it's just a matching service, you're on your own, and they may hang you out to dry if it suits them.
Regarding student matches, be aware that in most markets there are plenty of tutors, so respond to posts the instant you see them. Any that are older than 24 hours don't bother with, they're probably setting up their first meeting already.
Hope this helps!