Since .357 mag is not being used by any agencies what you find once fired is mostly mixed range brass. I don't like the idea of using mixed brass for a high performance round, that plus the fact that Starline Brass is only a few dollars more I would recommend you check them out.
Starline Brass - Maker of America's Finest Handgun Brass
I gave up on trying to find decent once fired 357-M brass. I have an order in with Starline now. Its on back order at present, but when I do get it, I can be sure that it is good and not multi-fired range pickup.