Jimd,
From your comments referring only to the tweeter and crossover I'm guessing these would be the Series II. The Series III released this year have carbon-fibre midrange units, as opposed to the magnesium ones in Series III. The latest one also has a port on the front, according to the Coincident web site. Also, the midrange units are mounted in cutouts so the frame is flush with the front baffle, whereas the Series I and Series II had these drivers standing proud.
The woofer arrangement gives flexibility. I have my Eclipses on the long wall with plenty of side clearance, so I have the woofers facing out.
I have not done a comparison either. I must say that the Supers sound, well, "super", in my system. They don't come up that often on the second-hand market, which is a guide to the level at which they are appreciated (I think so).
Regards,