I've used headset mics for years as I hire radio mic equipment to local schools, theatres and amateur dramatic companies. I've been through all sorts of low cost headsets trying to find one that sounds decent and will last for more than one hire to a school. Many come back bent, cables broken, parts missing, failed due to sweat, or just not sounding as they should any more. It's not always possible to charge the hirer the full replacement value as we value future hires.
I can't afford the likes of Countryman or DPA and have been looking for something that's better sounding and more robust than the cheapies, but not in the £500 region of the industry standard ones. So that's the rationale.
I bought 2 to try on a fairly high profile show, with professional singers, and they didn't disappoint. The talent said they were very comfortable and easy to adjust, and I found I got a good sound with less severe eq cuts than I had to make with cheap headsets. It was defined and crisp, and didn't distort event with a very powerful soprano singer.
The only downer is that I use JTS and Shure beltpack transmitters, so I had to cut the 3.5mm jack off and solder on a mini XLR connector.