I bought this for a Besson Sovereign EEb tuba (982) and the fit is perfect. Lots of protection with all the foam inserts. As a bonus there is a 'music' pouch and a 'mouthpiece' pouch on the outside of the bag that weren't shown in the pictures.
Back pack straps are comfy enough, the material is strong, everything seems well made.
Time will tell, but initial impressions are that this is an outstanding gig bag, with lots of protection.