I'm with CAV, I have only used Big Cheese when ordering mice. The product was super clean and vacuum packed (which is nice when buying large quanity to save a little on shipping)
Now, I breed my own mice and if I have to supplement, I use a local supplier.
Chad Martin is the propreitor of Big Cheese and he is very helpful and willing. Give him a call and tell him the folks on the corn snake forum recommmended him. He'll take care of you!
www.bigcheeserodents.com
There are a ton of other places as well, Big cheese is the only one I have dealt with. I believe Rich and few others use
www.cajunmice.com and have had great success with them as well!
Rodentpro is a big toss up. Some swear by them and others that have tried them, can't stand them. I have no opinion but if I got nasty dirty mice, I wouldn't be too happy!
Pick up a copy of REPTILE magazine and thumb through it, you will find countless ads for companies ready to sell and send you frozen rodents! Many more than I found just doing a google search.
Good luck,
Quigs