I haven't, but there are a lot of videos on YouTube by people who use them on RVs and boats. The technology has been out for years, and many people like them a lot.
It seems to me that they are better for those who use them an extended period of time or very frequently. For infrequent use, I think a cassette would be better.
Not sure if these would be the best for camping?...but I am going to try one in a building/cabin that has water and a grey line drainage without sewer.
Being able to separate/dump the urine is apparently a key feature in making these work well.