Pentax uses inserts not separate film backs(no mid-roll changes), has a focal plane shutter(slow-ish sync speed), built-in metering, motorized film advance, good glass.
Bronica has film backs, leaf shutter lenses(synch at any speed), crank, speed grip or motor advance options, modular finders(non-metered and metered), good glass.

Both are affordable entry-level system cameras.