Pros
WyzAnt is ideal for taking the grueling administrative aspect out of starting a new tutoring venture, be it for extra income or as a springboard to a full-time career. They make it very easy for students to find quality tutors safely and securely. WyzAnt handles the financial end (not taxes and at a steep initial overhead, see below) and disperses payment bi-monthly. WyzAnt does offer good incentives for improving your rating through advertising and blogging.
Cons
WyzAnt's overhead is pretty steep, so for a tutor just starting out it is pretty 'expensive' (i.e. only 60% of the targeted hourly rate is received). Also new tutors have to compete for local students since 'cold bids' for tutoring jobs is nearly futile. Students will eventually start coming to you once you improve your reputation and experience.