I find the Arban perfect near nearly all aspects of tuba playing, if you have the ability to make it so.
The Arban was great for me, as the first tuba solos I did were actually for tenor horn, thus needing to push the upper register higher than most badns take tubas.
Needing to develop sight reading? Arban is great. Hundreds of pages, you can't tell me you've played them ALL!!!!!!
Transposition practice? Good one for you Mr Seedhouse. You know how it's meant to sound normally, now try transposing an Arban exercise that you like! Read it as Concert Treble, Eb Treble, take it up a 3rd, a fifth. Play it up (if your stupid) or down (if you have the lungs) an octave.
OK, so it isn't specialist practice. I have other tuba and trombone books if I need to focus. But if I am out and about and feeling the need for a good blow on any instrument, the Arban is a practical text.