If you are snapping hex drivers, you're applying way too much torque. There are two relevant failure modes with steel for the purposes of hex drivers - torsional shearing (breaking) and deformation (stripping or twisting). Harder drivers will not deform, but may break with excessive torque application. Softer drivers won't snap off, but will twist, strip out or deform. You pretty much choose your evil. Personally I'll take a harder driver any day. The number one killer of screws is ill-fitting drivers due to oversized torx/hex sockets or undersized drivers. If these are both correct, failures are pretty rare. If you have a softer driver and a mating fit that is loose, it will often deform the driver almost immediately, affecting all future uses. A harder driver will deform the screws instead.
My personal preference for brands is Wiha, Wera, Felo in that order.