Pros: Unheard of sound quality and build quality at its price
Cons: Not the most isolating IEMs.
Allow me to preface this by saying that I have way more experience with headphones. The only IEMs I've ever owned before this were some cheapie $20 Sony IEMs, the MeElec CW31s, and the MeElect M9-BK. I've sold every IEM I've owned before this one, mostly because I felt like they never got any head time compared to my full-sized cans.
The packaging for the 8320 was about was minimalist as you can get -- there were the IEMs with inserts already on, no alternative inserts, no box, just a small plastic bag.
The design felt pretty solid, especially for a headphone of its price. The clothed cable was a nice touch and felt like a definite step up over typical cables for low end earbuds and IEMs, but it did feel cheap. I did find that they very often got tangled. I'm actually very impressed with the durability of the cable so far. I've already accidentally hard slammed the car door on this cable, pulling the Monoprices out of my pocket with such force that one of the tips flew off and they still worked perfectly afterwards.
The comfort could be better, but I'm not a giant fan of cheap IEM comfort. The lack of additional, different sized inserts is somewhat annoying, but they're also $7. The comfort is acceptable, but not something I'd want to wear all day.
As for the sound, the bass is tight and punchy. The sub-bass isn't quite that extended and you get the typical dynamic driver drop-off at the sub-bass frequencies. Bass had a solid amount of impact, but the rumble made bass-heavy electronic music feel a little lacking. Overall, though, I found the bass response to be solid. The mids had a surprising amount of clarity. By no means was it crystal clear, but it was better than I remembered my CW31s. Overall, the details in the mids and highs was solid.
For the price, I give the Monoprice 8320s my highest praise. They're certainly not hi-fi audio, but they're absolute monsters in their price range. Most $7 earphones sound and feel like absolute crap, but these could definitely compete with the $20-40 MeElecs.