I would say this earphone is about average compared to other in-ear phones within the same price range.
It does the job and it is far more durable than cheaper earphones. However, the customisable attachments feel cheap and fall of the earphones easily when not in use. The most important bit for me though is the sound and, although better than cheaper alternatives, for the same price I think you can get something better. In particular, the volume can't go up by much, which is annoying when you don't want to hear the gym music in the background.
So all in all, an OK earphone that does the job (and is far more durable than most cheaper earphones). However, for the same price I bet there are better alternatives.