I could never get the 8320s to fit right. I put on smaller tips (helped a little), put the cord over my ears, in front of my ears, twisted the bud...my ears just aren't big enough.
The 8320s suffer mostly from a bizarre design. If Monoprice would put the same guts into a standard, straightforward bud I would buy them in an instant. Soundwise, they are on par with UE SuperFi 4s and MEElectronics M9P, but with larger soundscape. All of the instruments are very distinctive, even on crappy 192 AAC. Isolation is poor with the stock tips, better with smaller tips, not great overall.
I wanted to like these so much, but I can't stand wearing them. They're too big for me, the cord is always tickling the back of my ears, and there's something very sharp poking me when I adjust them. I replaced them with Panasonic RPHJE120Ks which are the most comfortable IEMs I've ever owned, though the sound is much, much thinner. I wear them 2+ hours a day, so comfort wins out.