I vote for the evo (hell that's what I did).
I had an SL, but found it too stiff for my skill level. See, I suck. At pressing and stuff like that. So I sold it, and now have an evo. Once I get better, then I'll be able to press other boards. Fact is, I don't get a lot of time on the mountain so I need to maximize it, that means a softer board.
The SL and Proto have similar flex. You don't have to be in the park to enjoy the Evo. Sometimes you can treat the whole run like a playground, which is what I want to do, since I want to stay out of the park for now while learning to goof off.
The Evo hype got me I bought a westmark and sold it before even riding it. Broke even though. I'm sticking with the evo at first learning to press and get my balance right, then I'm jumping to arbor just to test the waters. If I were you, my quiver of two would be evo then something more powder/freeride oriented. The Proto and Evo are quite similar at the end of the day. The only thing separating them is flex.