If you go back to the left picture in reply #40. This is the reason I have this opinion. Basically the size of the carrier section.
Generally in drivetrains when all else is equal, smaller is not better. You can hold a door open by sitting a cinder block in front of it or stuff a piece of cardboard in the door jamb, both will hold it open but one will hold it better. Off road guys do not run the 9" for that very reason.
I'm not doubting your differential has not been trouble free and reliable. It's like arguing over what is the best bearing grease. They ALL have their pros and cons. For a street car it needs to be mentioned, the best is not the best in every category.
So basically there is 100 reasons for each decision for each car/person. Since my car is not fast, efficiency is important to me and I refuse to run a spool on the street. A Tru trac diff was chosen and I wanted a big TruTrac. Also had interest in keeping a GM rear under my car, even though they are not the strongest, I chose a 12 bolt.
The market value of an 8.5 was also considered. If I broke it, the value would be $0.00. So I sold it for $2500 and that almost paid for a brand new Moser 12.