I've had this for some time and didn't have any issues with it.
The microphone and wireless pack feel solid. The receiver feels a little light, but inspecting the electronics, it all looks good quality.
The wireless pack internal electronics are not conformaly coated though, so over time, residue from sweat can cause issues (friend had that issue and I had to fix his pack) which is a bit weird for a kit specially marketed for fitness trainer (where obviously you sweat when exercising ...).