I replaced the Aqua Magic on my 20' Argosy with a Bravura but because it is deeper in the back, I had to cut the silly little storage compartment behind the toilet off, the one that was there on the Argosy. I like the Bravura, because it is a larger toilet, but because it is larger, it is not a direct replacement for toilets in close quarters. Thetford does not make this clear in their literature.
I had no problems with the flange, or seating. Mine is solid, like the original was.