Pros: Not very expensive
Cons: Awful sound
Having been a marketing casualty years ago by the Sennheiser headphone giant having two decent over-ear headphones bought of them, I decided to have these for an MP3 player additionally seeing good reviews about them.
I don't know if eartips of them not fitted well in my ears but the sound was awful!!!
I can't say enough about mids, trebles, basses etc. but overall the sound was harsh to a point that my ears couldn't stand the dreadfull noise of them!!!
As I was a newbie in IEM's it was a traumatic experience as it was difficult for me as a music user to buy another in-ear after them.
As I pre-wrote I hope there were the tips not fitted well in my ear canal because I didn't expect such a drawback from the Sennheiser company.
I don't recommend them at all!!!
(A day before the review I tested (without burn-in and Comply foams where I am an admirer) the Philips SHE-3590 and they are much better than 300's and they cost lower than 10 euros!!!)
Anyway, test them before you buy them.
Have a nice life, yannisgk.