All three are fine horns and I've played and/or owned all three. The obvious answer of course is to try and play them and see what you like. A couple of alternatives however: It was me I'd check out the Sonare along with the Challenger II-- a B&S with a Blackburn leadpipe. Also if you like the Connie the Kanstul "Maraichi" is an an exact copy of Snooky Young's old Connie. Chances are you'd have lot fewer "issues" than buying some old Connie 40+ years old with shot valves, loose compression, abused by some 5th grader, etc. The Maraichi is a unique playing horn-- 437 bore with a big bell. A blast to play but it's like catfish, people tend to really like it or not care for it at all.
Kanstul Mariachi Trumpet - MAR991