There are way too many tenant screening solutions out there all competing for your business, and most of them are not worth what you pay.
The key to finding the right tenant screening service is simple: call the number listed and speak with someone. If you can't talk with someone who will tell you why you should be using their company, then don't use that service.
For me, I called a few different companies, and ended up talking with low-ranking salesmen and customer service reps who were the least bit helpful.
Then I called TenantMagic, and in seconds was connected with the owner of the company, and we had a fairly long and interesting discussion about what differentiates them and their service. Highly recommend TenantMagic for anyone out there looking for a great tenant screening service.