A great quality small spinner from Travelpro.  Great hardware that moves easily and smoothly at all times.  Good, sturdy, solid handle which has a generous height for easy management.  Expensive, but worth the price.  Should last for years and years.  Perfect size for music scores and standard paper and folders.

The only caveat I have is that, to get my papers and music inside the main compartment, but front panel must be unzipped all the way down.  This is good, in the sense of security and safety for what's inside, but can be terribly inconvenient when one wants to get in quickly just to slip a paper inside.  Just a quirk of this design.

Can be found on sale rarely, but keep looking.