The difference between Magneplanar 3.5 & 3.6R

I recently traded Martin Logan SL3's for JM Lab Electra 936's and, for the most part, am very happy with the Electra's, especially with their reproduction of the high frequencies. I have missed, though, the sound, however one wants to describe it, of the electrstat and ribbon speakers that I've mostly used during the past 20 years. Several days ago I auditioned a pair of Magneplanar 3.6R's and am convinced that, if I could find a way to justify the expense, I would own them w/o hesitation. In reviewing what's available on the used market, I came accross MG-3.5's and would like to know how they compare with the new 3.6's. I would be driving these with a MacCormack DNA-3.