I haven't used one personally, but my understanding is that they work as advertised.
I just don't think they are really popular because people tend to buy actual touch screen monitors for computer use, and most people don't need to add touch screen functionality to their larger "TV sized" screens. Obviously there is a use case for them however and I've looked into them previously when exploring some projects myself. I just never got to the point of pulling the trigger on one because the "use case" we were considering them for never made it past the exploration stage.
