I am quite sensitive to treble, and have little love for harsh treble and unless I have a very different definition of harsh, the 880 does not have harsh treble. The HF2 was considered to have some of the better portrayed highs for Grados, sounds like the MS1 which a fellow head-fier brought over to my home for a listening session. When he heard the HF2 he couldn't believe how similar to the MS1 it was. The 880 in my opinion has better treble than the HF2, detailed enough to be revealing, but not harsh. I listen to music quite loud, and if the treble is harsh, I can't bear it for long. The 880 is not soft of course, but in my view (and of course many other peoples view) it balances well the opposing goals of detail and listenability. Certainly hear some for yourself, don't just believe that they are harsh because others say they are. There are many posters here who think the 650s are not very good, and yet many would differ. Only your ears will know. If your in New York you are sure to find a store that carries both Beyerdynamic and Sennheiser, give them both a good listen with as many genres as you can.
The only way to know is trying it out for myself. People say it's best to go to meets, but I have no idea of what a meet is, could you explain lol?