There is no one-size-fits-all solution.
The cassette is more work.
We empty and rinse ours daily. It will last us (2 adults, full use of camper facilities) 2 days, same as the grey tank, which also gets emptied daily via a bucket.
We do not use any chemicals or SOG system. There is no odor problem where we travel. That might be different in very warm climates.
We have never had a problem finding a place to dump the cassette.
If you usually stay long in one place, or even in a full hookup campground, the cassette is probably a disadvantage.