Hard shell or semi-rigid
A full hard shell gives maximum protection and minimum flexibility. Semi-rigid cases, with a reinforced frame and softer panels, absorb a knock and still accept an extra folder. For daily commuting, semi-rigid is usually the better trade.
Carry options
A top handle is the default, but a detachable shoulder strap changes what the bag can do on a crowded platform. Look for anchored D-rings rather than strap loops sewn into the lining, which is where cheap cases tear.
Inside the case
You want a dedicated padded laptop compartment, a separate document section so paper does not scratch the screen, and small organizer pockets that keep cables from tangling around everything else.
