I purchased this headset for use as IEM but also for listening to music on my iPhone. It is very easy to connect via bluetooth. The sound is decent, has plenty bass. Overall quality is also decent, and battery life also is very good. Battery is charged via USB-C. It is comfortable to wear, also when active. No stress about loosing airpods as both earpieces are interconnected. I like it but...
I also have a Shure SE215 and for use as IEM it functions better imo. Bass is louder, mids are there where you need them, particularly as a singer, and highs are crisp and present. The Sennheiser sounds a bit muffled in comparison. The Shure is about the same price but does not have the bluetooth. It is however much sturdier, with stronger wires which are reinforced also. Unlike the Sennheiser, the Shure blocks out ambient sound pretty well, passive noise canceling.
All in all, the Sennheiser sounds more hifi but in a band setting the Shure works so much better.