Bach 351 Trumpet 9D

I'm surprised this mouthpiece is not better known and more widely used - fairly close to a 7C diameter but for me a more comfortable, less sharp rim. The 9D is definitely NOT a very shallow cup, I would say slightly deeper than the close equivalent Yamaha 11B4. The cup also has a slight V shape to it, a bit of a V/C hybrid. I also have the 9C and that is really quite deep, more than I was expecting. Deserves to be better known in the Bach catalogue.