Nearer 10/90.
There are good ones out there, but they're the exception rather than the rule. Obviously check here for reviews, but I've found a couple of things that help identify potential.
1 - Long term locations or regular touring slots. This indicates return business which has to be a good thing.
2 - Regularly updated pictures which aren't professionally taken and where they look like they're actually enjoying themselves.
3 - Profiles & Phone numbers which aren't recycled from other girls.
None are guaranteed obviously, but I've found a couple of decent ones in the past using that as a guide.