Ah, Survivor, the other overpowered Prestige Class you can take at second level.
Well, at least I like the idea of Survivor better.
edit: Though, the class you want to hit Survivor from isn't eligible until sixth-- Monk. There's a little overlap in the Evasion tree, but Uncanny Dodge and Damage Reduction make Monks pretty close to invulnerable.
Going in at fourth level from Fighter/Rogue, though, is a lot nicer, with your Uncanny Dodge stacking. You also don't have to use one of your pretty Special Abilities for Improved Evasion, if you ever reach Epic-level play.
I think the class would be improved considerably by putting in some prerequisites that apply to survival-- Endurance, one of the saving throw feats, or even Toughness. The less normally useful the feat is, the better.