It's the player, not the horn, and you know that! :-)
But really, what a difficult question to answer. Any biggish 4/4 to 5/4 tuba that plays well and you like the sound, that's your answer.
If it were me, the things I would look at would be:
Alex 163 ( one of the good ones )
B&S GR-41
MW2145 with an RT-88 (double secret bonus points if you can ever track down a BBC edition 2145. Outrageously good, I think they only made a few)
Nirschl 4/4 CC ( The handmade-est version)
A good MW-32 will also do an excellent job
Even in just the five instruments listed above, there's quite a variety in the type of sound that you would get.
The Alex 163 that I owned with spectacular, and surprising to me in a lot of ways. I had this expectation that it was going to be much bigger in size and sound than it was, but that wasn't exactly true. Physically, it was a lot like the 186-or 188, and up until a mezzo forte or forte, it behaved similarly as well.
But right about the point where a 186 or 188 starts to get ratty or a little stuffy or just starts to feel a little different... And starts to sound like you're pushing the instrument too hard... That's where the 163 kind of takes over
Instead, the 163 opens up even further and just keeps going and going. It's an unsuspecting amount of bigness at the top 25% of output, because everything else was nice and mediumish and easy to play
That is, you can kind of just chill out and play and know that everybody can hear you and it sounds nice. But when you really need to lay down some thunder, you can rain hell over the entire orchestra and still have rain clouds in reserve.
And after you're finished kicking ass back there, stroll out front and play a pretty little solo as if you didn't just do what you had just done.
Like the tuba version of a tough biker dude in full leathers and all tatted up... but also has a cat named Petunia, and you'd better not mention it.
Just get one with the intonation doesn't suck
and the front Action 33s BBb and the 90 front Action CC...
