In either one of those boats, have a good surveyor check for rot / moisture in the stringers and transom. Personally, I've always been of the opinion that most Scarabs were built better than most Bajas. Both of those brands had hull blistering problems in certain years and Bajas in general have had some pretty wimpy stringers around the engine mounts.
What engines / drives do they have? How many hours? Salt water or fresh water? A quick check of the fluids (engine oil, drive lube, etc.) can tell you a lot about the condition of those bad boys.