HI, guys!
I play a Mirafone three valve Bb flugelhorn. My wife has a Kanstul Copper bell three valve piston flugelhorn. She loves hers, and I like mine. I'd like the Mirafone better with third valve trigger, but it's not too badly out of tune and I can lip D's down sufficiently.
I've also played the Czerveny rotary, and found it ok.
I've bought a couple of Czech antique flugels as well, one with four valves, and a couple of Russian flugels, and found them wanting in the intonation department. Good thing that they were relatively inexpensive.
That's my experience, anyway!
Later!
Guy Clark
South Bay Brass