Don't trust tutor referral sites for these reasons.
1. They are not safe!You have to have a stranger in your home or wait during sessions in public places like libraries. They hire whoever fills out their application and assume that the person has the education and background listed in the application.
2. These referral sites have no resources. The tutor shows up with paper, pencil, and maybe a laptop. Maybe you build a relationship with the tutor. However, are you ever going to feel comfortable leaving them alone? You have errands to run and things to do.
3. Referral sites simply cannot give the benefits, safety, and professionalism that a tutoring center can.