Jr. Gent II superficially looks like the Baron from Berea and the tycoon from PSI (the tycoon has an unattractive double-band IMO).
Looks are deceiving. I've never touched a Tycoon, but I know the Baron is a touch smaller than the Jr GentII, which I prefer myself, but not necessarily all of my customers. I try to stick to the Baron simply for simplicity (and because the Baron is available in chrome), but if I have a customer that wants something bigger, or if I want a rhodium with gold accents (the Baron has black accents) I use a Jr Gent II.
Tubes don't match from one to the other and the bushings are not the same.
The bigger fullsize Gentleman is a very nice pen for those that want to write with a chicken leg sized pen. I sold one the other day and the guy was absolutely enthralled with the huge nib.