I would get the Stainless if it were my gun.
Stainless is very rust proof and easily fixed if you scratch it. A lttle 1500 grit paper is all you need to make it look like new. I have a stainless stinger and I love it, I also sweat on it allot with a blemish yet. I do however clean often and coat with Militec or CLP to prevent any problems. Tuffness in my opion is also the stainless because there is no finish over metal at all to deal with it's just SS that's it!
ps. They are both great finishes and I recomend them both, I think you would be pleased with either of them.