The good things:
Th bag is nicely made and seems of good quality. My tuba is a Cerveny Harmonia III F-tuba, an older modell, 36cm bell and it fits perfect.
There is one pocket for sheet notes and I put the mouthpiece in the smaller pocket on the side.
The little disadvantage:
I like to use the bagpack straps but unfortunately you'll get the bell against the back of your head, espeacially when your cykling or wanna wear a hat.