Some people like those things, but the problem is you can't really sell them on eBay. If you repair the stuff maybe make it a garage project and then try to resell it on Craigslist, but I have doubts about that.
Tell you what impressed me about SOME of those old Maggies was the speakers. I had a set of woofers and horns from a TV stereo combo and they rocked once applied with a differnet crossover, EQ and a real amp. In fact, a set of those, with modified crossovers, runing off an RS amp of probably less than 50 WPC brought the cops to my place form a different city ! Extremely efficient. Efficient to the point where you got room to EQ, and they need surprisingly little of it.
When you see those, look at the speakers. there are two type os horns they used, one has a metal back, usually green. Then there is a type that is larger and has a styrofoam back. the styro ones are inferior to the metal backed, smaller ones. Also, if you get one with the 15" woofers, the ones without the external pole holder or whatever you call it are the superior. Imean they are still alnico but they to not have the formed metal around them. Like a sealed alnico. those woofers are quit good. If you stick them in a proper cabinet with a proper crossover (which the Maggies did not have because they took care of it with EQ in the amp) I do believe you will have some close to a set of Klipsch. EXTREMELY efficient and sound good.
I lived in Rocky River and a pair of them brought the cops across the river from Lakewood...