Quote: Thanks for the reply. I am looking for something that will mainly be used in my home office and at my work office, both of which are private. So I was initially prioritizing sound quality and comfort above all, but the chance to get something portable and comfortable without sacrificing too much in sound quality is appealing. Reviews of the COP have been mixed, whereas all of the feedback coming in so far on the M-100 has been really positive, especially in terms of SQ. But as of right now, the M-100 are twice what the COP cost. If I'm going to stay in the Beyer family, though, I want to get the best sound, and it seems like the 880 or 990 are better reviewed than the COP. Trying to avoid dropping cash on something that requires an amp to get acceptable sound.