Trying to answer your original question.
There are 3 28's at our Iowa marina. All are very well kept, fresh water boats. I've been sailing my new to me in August of 08 and competing in Wednesday night beer can races. I replaced my headsail this spring, but sail with the 1993 original main and am able to finish in the middle of the pack against Capri 22's, Catalina 30's and 34's. I haven't had to put a lot of work into the boat. However, I wonder about the condition of the 28's that you are looking at in the $20,000 range. I paid $30,000 for mine with trailer, replaced the headsail, added adjustable Genoa tracks and a back stay adjuster.
Good luck in your search.