I just bought two AS Cadet Pro's from the local supply house to replace my 1993 Crane's which came with the house (one of the tanks spontaneously cracked the other night, I have no idea why, and thank God I was home at the time).
I pulled all the part numbers and spec sheets for the Cadet's internal parts. Comparing to the equivalent version of the Cadet 3, the Pro lists additional features of "Robust metal trip lever & metal shank fill valve" (indeed, it has the version of the Fluidmaster 400 fill valve with a brass shank), a "Trade exclusive tank", and the part numbers for bowls and tanks are different. How else should I expect the Pro version to be better? Just curious.