Not too much clarity on the best ones for Marching. A little review, from my opinion:
Yamaha: Only one with a large shank mouthpiece receiver. Easy to control in the lower register. Overall good tone. I do not feel they equal the projection of other available. Often the baritone of choice for high school marching.
King: Light-weight baritone all-arounder. Tone suffers and stuffy in the low register. Intonation’s not that solid. Used by high school marching bands mostly due to low price and being light.
Dynasty: Great tone and projection. May have intonation problems, and the low register isn’t great. Also
common in high school marching bands.
Kanstul: I like this one best. Beautiful tone, projects well, and blends as needed into the ensemble. Excellent intonation. Too bad not many high schools use them as they’re nearly as heavy as marching euphoniums and cost.
If your price conscious and can’t go Kanstul, depends what you prefer: If you like tone over low range go for the dynasty. If the large shank receiver and overall satisfactory is more important, the yamaha. My two cents!