Guy, the 3 elements is the best of Elmars 90, definitely (keep this for sure,, they are a specific passion for me... I have 7 all different
). For me, better also than the Elmar C for CL : it's compact, light, robust, good for macro (lenshead is removable for Visoflex use) : the BM version (which I have) isn't so rare... at the moment, a quick look at Schouten and Beimeister reveals 3 for sale ranging 400 to 750 Euros (this last, imho, is a sort of top price for a very fine item), the SM version (which I haven't) is much rarer but, for me , the 3 elem. is above all a usable little tele for film Ms and M8... the SM is a piece for collecting (Schouten has also for sale a super rare 3 elements with a strange, pre-series mount... stellar price)
Has a std. E39 filter size, so no problem with UVIR, and also the lens hood (IUFOO/12575) is easy to find.