We have a camp situated on a sensitive body of water (the drinking supply for the city we live in 75 miles away) and didn't want to have a composting toilet and a septic was out of the question because of very limited access to the size for heavy equipment and the lack of running water.
Service has been really great for the few issues that we have had. Prompt and was able to text them from camp when I was working on the toilet.
We've had it at camp a year now and it continues to just do it's thing. We bought the TinyJohn and in retrospect I probably wish I had bought the XL model. We just have too many guests at camp some weekends for the smaller version to keep up. This is also due in part to kids/user error. Ha! There is a delay between when you push the button and when it flushes and if you sit there and mash the button over and over again, it sometimes registers multiple flushes I think and adds extra time.
I think in a year I have only had to swap the propane bottle once and we are about to go to a much larger 100lbs tank and add a hot shower. I think in all that time I have emptied the ash tray maybe 4 or 5 times.
It's really a pretty amazing device and by all account online, they last a good while and are serviceable in place (important to me, again because of very limited access.)
Overall, very pleased with the device. It's pretty great for what it does and allowed us to meet all of our goals with limited access and specific requirements.