Although this is not a fair comparison, I own the SR80's and the DT880's. I bought the Grado's after hearing how amazing they were for rock, etc. I was pretty disappointed with what I heard. I felt like the bass was missing any kind of authority, and the whole sound had a very one dimensional feel to it. There was no heft, no weight behind any of the notes. Yes they were very quick, but I guess the Grado sound signature is not for me. I have heard that the issues I had with the Grado's only marginally improve as you climb up the product ladder.
Now the DT880's are an entirely different story. Although some claim the bass to be anemic, I find it quite satisfying. IMO, it's much, much better than the Grado's bass. It goes very low, and has a satisfying weight behind it. It's not the strongest, but it gets the job done. It is there when the music calls for it. The treble is rich, and the sense of air is amazing. They are both involving and detailed, something that I feel is rare. I didn't think I was one for a neutral, analytical set of cans (hence the reason I originally bought the more colored and "musical" Grado's), but after hearing the Beyer's I am hooked. You can get caught up in the music listening to them, or just have them on and forget they're there. I have no trouble listening to rock with them, you can hear every detail there is to hear.
Of course the best solution is to demo them, but if you can't, I'd say go with your gut. I muddled over this latest purchase for weeks and weeks, and finally went with my gut and got the beyer's. Trust your instincts!!