I just had an opportunity to play on the new King Bb Contra (notice how I avoid the term tuba). I loved it. It's smaller than a Kanstul, yet it plays a lot better. It sounds like my King Tuba. Ok, so maybe I'm a bit bias.
I like the 4th valve placement. It's on the left side and you use your left hand to operate it. It would have been better if it was a rotary valve instead of a piston, but it was nice. It's shorter than the other contras I've played, so drill writers will be able to have contras move in tighter spaces with a better probability of not hitting the horn.
I think I'll get me some for my program.
;)^