I realize that Tutorvista has gotten some positive press from some major news outlets. Maybe they do provide a good service to some but I feel there are some things that any prospective customer of the site should know.
The first thing is that you'll never be able to be positive that you're being taught how to solve a problem correctly. We got two different answers to one problem, both of them wrong. Secondly, you have a time limit for your sessions and if you're not done, too bad. And there are gaps of up to 5 minutes in response time so you're 30 minute session can get used up pretty quickly.
Also, they have a "strict NO refund policy" to quote the customer rep who handled (or I should say didn't handle) my refund request. They claim to offer free help to get you started but mostly what you'll get is a hard sell to "get an account" before getting any actual help. I would caution anyone against using this service.
Review about: Tutor Vista Tutoring Service.