Pros: Great sound, once broken in the mids are very clear.
Cons: You need to burn in these headphones, otherwise they sound flat.
I bought my first set of 8320 two years or more back. They were very flat in the beggining then someone sugested these should be burned in for a few days with white noise. An old cell phone and white noise generator helped break these things in. Man o man what a difference. Made my bose IEM look like dollar store headphones. Sound is a relative thing IMHO just like taste in food. Some like certain foods more or less. I stopped buying other types of IEM's. Simply put these are the most durable IEM's I have ever had, once you perform some choice upgrades they can be awesome.
I wore these for more than 2 years daily for at least 3 hours a day. They have never let me down.
My suggestions would be as follows.
1 - Get some better tips for these.
2 - Get a set of earplugs and cut them short and puch out a hole in them. Put them behind the tips for extra spring.
3 - do not forget to wrap the cable behind your ear to reduce microphoning of the cable. (Helps tremendously)
I even designed a 3d printable holder for these so you can store them in style. Here is a link. -> https://www.youmagine.com/designs/monoprice-8320-headphone-holder
I Even bought two more pairs to keep as spares as these after 2+ years are looking raged, but they are still 100% functional. If I bought 10 pairs I could have a lifetime supply of these.