What's wrong with the SL guys? That's a great all-mountain freestyle board with great reviews all over the web. You want something for park and groomers, I feel you'll be doing more jumping than rails? I think both Evo and SL are great for you, and you shouldn't ignore that great deal.
If you want lots of buttering and rails: Evo
If you want all mountain performance, great jumping and a bit less (ofcourse still possible) jibbing: SL
If you think that other one is exacly in the middle, wait. But I don't think it will make a lot of a difference, it won't be exacly in the middle and you'll still be making the same choice as you're doing with these two boards