Yeah its good... but be careful buying from people with < ~93% positives, and definately not from people with < 10 score.
Read the auction *really* carefully. There are a lot of scum auctioneers who will put "MINT condition" etc. in the title, and then in some tiny text, in the auction, they will say "no case, no manual, scratched all to heck", or somesuch. Or the shipping will be outrageous...
As long as you read carefully, and check the seller's rep, PayPal will protect you from people who break the rules.
I usually end up getting the best quality used games from normal people, who have near 100% positive reviews, but often have scores in the 30-200 range, and not in the 1000s. For the most part, its just normal folks trying to get better than what GameStop will give them.
Remember "if it looks too good to be true, it probably is", and you're set.