i have a similar wetbath setup.
i had a dometic 310 in there when i built it. it lasted 8-9 years maybe 10. i broke the lid of the toilet while showering. i used the toilet like a bench and threw my leg up there to dry it off. my weight of my foot broke the lid of the toilet.
replacement lid cost was close enough to the price of a new toilet that i went with a new toilet last year when i replaced the dometic.
i was at camping world and limited to the choices they had in stock which was not dometic. i think i got an thetford this time.
for me, the important things are tall, porcelain, and oval.
i don;t see any quality difference between brands, i'd expect a similar life out of this toilet too.
i got to change the toilets out in a strip mall parking lot. its a quick easy job. but i remember asking the local taco bell if i could use their dumpster for my old fixture..... i didnt feel bad leaving it there.
here is an old pic of the original toilet.