I totaly agree with that. When I first heard of the rule chance I thought "Why does Blue Devil and Cadets want to do that" They said that the Bb horns were much better to play. and I thought, is Devils hornline that bad ??? I don't think so. They were very good on to G Bugles and they are very good on the Bb.
I do think that you can see them as two different flavors of icecream. I like icecream a lot but I like the G flavor a litlle bit more. It is hard to explain why, try to explain to another person why you like vanilla ice (not the fake rapper ) better than strawberry , especialy when the other likes strawberry !
For me the G sound is a brighter, more "ringing" sound. You can play in tune , you just have to work harder for it.
Excuse me for the typemistakes, but on the other hand, I type better in Dutch than you do :P