I use these for amateur plays and musicals. At a recent show, some performers used more expensive (taped-on) Sennheiser over-the-ear mikes and some performers used these. I was surprised how well these sounded... Very acceptable sound. I recommend using a high pass filter, 200 Hz cutoff, to eliminate rumble noises.
Our preists also use these at our church. They have worked reliably for many years.
One big advantage is these are omnidirectional. I have had difficulty with amateur performers keeping unidirectional lavaliers positioned vertically. With these, rotation doesn't matter. Theoretically, omnidirectional mikes pick up too much peripheral sound... I have not found this to be a problem.