Just got mine, and after letting them sit on my desk for 3 hours burning in, I threw on some Alice in Chains (320 kbps). I have never heard guitar sound this textured before. I'm in a happy place right now! They have such a different sound then my m50's, more musical and fun. I'm going to get a big jar, and start throwing change in there for the rs1's. I hope I can give myself 3 years before I bite the upgrade bullet.
Don't spend your time worrying about the rest of the line, the SR-80's sound rather close to the RS-1 if you've ever listened to them side by side. It's just that quality is in the details, but it's generally the same sonic signature.
I feel that if you throw someone an SR-80 or an RS-1 for the first time, they'll most likely be just as impressed. Grado gets you with the whole "one headphone, many models" thing, but I usually say, just pick the one you can afford right off the bat, and until something changes where you just plain want to pay more money for a Grado, you'll be right at home. But after all who doesn't love new toys? (ask my knife collection)