Having played all three of these models at one point, I wouldn't say that the Geneva sounds like a baritone or really has a baritone-like quality. I've heard that from people before when comparing the Besson Prestige to other models of euphonium, and I think that misconception lies with the fact that the Prestige has a very specific sound profile. I think someone on this forum (maybe Don?) said at one point that a Besson Prestige is a great option if you want to sound like Steven Mead. Now, while I don't NECESSARILY agree 100 percent, I understand the sentiment. The Prestige has a very soft, "rounded corners" feel and sound, which I think can make any other model horn feel a little harsh when compared side by side. I personally prefer more brightness in my sound than a Prestige typically offers, but as always, it's up to the individual.
Sean Kissane
Low Brass Specialist, Paige's Music
Principal Euphonium, Indianapolis Brass Choir
Principal Euphonium, Crossroads Brass Band