Pros
The best part is being able to work from home (or anywhere you have Internet connection). It's a fairly easy job if you know the subject and when I started they had a lot of subjects to choose from. It's nice to be able to log on when you have free time but that doesn't mean you'll have a student.
Cons
If you tutor anywhere else you will most likely be paid more. I think you get paid less due to the convenience. The time limits can be ridiculous, some students need to spend additional time on a problem compared to others but you'll be criticized no matter what the reason is. You can do two sessions at one time and your pay increases by a small amount, I don't think it's worth the trouble to try tutoring two students at a time though. As a new tutor, I was never able to schedule hours, which means I only was able to float. If your a tutor 2 or 3, you can probably make a good amount of money by scheduling but it may take a while to get there. I don't think it's worth the time to get there.