One factor to consider in my mind would be freshwater vs. salt. It's entirely possible that the rigging on the Hunter, if its entire life has been on a lake, is original, which may be a consideration. On the other hand, it will, if it has been reasonably maintained, have less wear on the engine and winches than a salt-water boat of the same age.
As for Hunters, I think they fall into three categories: not bad/average, badly built, and badly designed. My sense is that the mid-70s Hunters were OK in the same way as a mid-70s Pearson was OK, and for daysailing on an inland lake, it would actually be a nice and spacious boat. For more than fair-weather coastal sailing on the ocean, maybe not so much at this point.
A Catalina 27 is a considerably smaller, and likely crappier, boat, particularly if it looks it at this stage.
I will admit my opinion of Hunters is greatly influenced by having seen one dropped and smashed, seen a couple out of control in 25 knots, and having looked in the bilges of a few at dock. The only recent Hunter I liked conceptually (because I wouldn't take "build quality" as a given) was the Hunter HC50, which struck me as a very nice boat, but I would imagine found few takers.