On the 3 digit Catalinas a "hull and liner" construction method is used, seat and galley bases are made from fiberglass as part of the liner. Most of the cabin sole is supported on a fiberglass pan with floorboards screwed down, access to space under cushions is a plywood lid on the FG base. On a Bene all the cabin furniture bases are "stick built" so bases are ply with elaborate puzzle shaped plywood covers.
Cat uses a FG box on front and rear for engine covers which are not insulated and noisey when motoring, boxes are easily removed from the boat for service. Bene uses a companionway stair/cover that swings up for access and is insulated with egg crate foam so very quiet when motoring, with insulated removable ply panels in aft cabin.
Catalina usually have 2 equal battery banks of 4D's with a 1-2- both switch, Bene's have a single start battery and 5/6 house batts size 24/27/31, they are switched independently.
For many mechanical items particular to the builder Cat could be characterized as using a KISS engineering approach and Bene a more " French engineering" approach. Organizer at mast plate on a Cat is stainless sheet with holes punched for shackles and turning blocks, French make a forged casting with machined hardened steel pin. Cat uses a FG companionway hatch with boards, Bene a plate glass hatch, etc.