I have never used a dump station. I have a readily-accessible sewer cleanout next to my garage/driveway, which is where I dumped a black tank when I had one, and where I dump the cassette toilet. I dump either after each trip.
Advantages of the cassette are I don't need a 'stinky slinky' stored in the garage. I need only two ounces per fill of the toilet chemical, plus two quarts of water, to start the cassette. The black tank needed 8 oz/5 gallons h2o to start. I have used a pit toilet (where I was staying)to empty the cassette on a longer trip, no need to look for a dump station.
The use capacity of the cassette is limited to much fewer uses than the black tank was. This might be a concern for someone who camps 4-5 days without moving and without access to any place to dump either type of toilet. I had no issue using the black tank, but I think I prefer the cassette style by a small margin.