I think situation is slightly different depending on the case, on what level you're operating... but basically I still trade on almost every level.
-I trade 2nd hand items, just scored from fellow board member copy of Isten#2, old Seed Mouth tape, old MDM tape (self abuse) which I didn't have. Or I think I don't. If I actually did, eventually back on trades or 2nd hand sales..
-I trade as the label/artist. Single copies for other peoples single copies or bulk copies for other people bulk. This includes my own works and stuff I put out.
Does one get some uninspiring crap once in a while? I guess so, but it also gives you perspective for the whole field. I know people, who focus on guaranteed big names they can trust, but what happens when they don't live up to it? Still keep eye on the same names out of old habits, while one cheap cdr or tape would suddenly reveal that there might be inspiring new stuff all around. If not new, at least unheard to you.
If material appears to be half assed, not "seriously" done, just something thrown together quick to have something to send around, I have no time for it. I think often you can somehow already have certain gut feeling what is the good choice. I do trade from the smallest self released tapes to biggest players of the genre, if they just can convince it is something I need to get.