Pros
I've only been working with them for a few months, but there is definitely a few pros. The hours are extremely flexible, you schedule your own or you can float (but you don't get paid for the waiting time when you float). It's also a very rewarding job since you are helping people. For your first few months, you also work with a mentor that will basically instruct you on your approach and offer some tips. I would pretty much recommend this job to someone who wants to earn extra money on the side or to a college student
Kontras
One big con is the dry spells. Usually, when there's no school in session, the site is dead. Of course, you get your one or few in the summer, but you have to wait a while before that even happens. It's also hard to schedule hours at times; unless you are the earliest day to schedule, it's hard to sign up for an hour. Also, not every student would want to work with you in the way the site wants you to work with them. Many just want the answer or want you to be quick. Sometimes it's hard to not get frustrated when this happens. Also, you only get paid to wait if you are scheduled for that hour, which is why this is really meant as a part-time job and not full-time. If you float around for a session (when you're not scheduled), then you don't get paid while waiting. You're only paid if you're in session.