Personally I like ebony the best, no doubt. It has the nicest feel to me, because of the density of the grain. Maple is similar, but most maple boards have a decent coat of laquer on them anyway, and that gives you a sort of false density feel. I can't say I've ever noticed much of a difference between rosewood, maple or ebony sound wise when you're going through a half stack, trying to fit nicely in the mix with your drummer and bassist, though. It's certainly easier to me to feel the differences between the woods than to hear them in a gig situation. The differences between an overdrive distortion and a fuzz distortion are much greater, for example. Don't know if that's any help to you. You should have at least one maple board guitar though, they're good for your soul
I wouldn't put much stock in a salesman saying one sustains better than another if you know you're going to be shredding through a distortion anyway. Spend your money on the one that feels best to you with your eyes closed, and you'll be fine.