I have had 3 of these now. They provide excellent quality sound for a very good price, not only on stage but also for studio recording. Provides a bright sound I love on my Alto sax, and is dynamic, no phantom power or battery pack needed.
The grip occasionally falls off the bell of the sax while I'm performing (moving round a bit) - which is not good.
However they do wear out, not the mic but the very thin cable which is vulnerable especially where it meets the clip (even Sennheiser agree), and I have had to replace them every 2 years or so. I hope they will develop a sturdier cable.