Had any more thoughts about the new ED vs. the F-ED. Is the primary difference the magnesium body and the products weight? (which is, of course, a legitimate consideration).

I agree with you that "The problem with labeling models ED/HD/etc. is that a lot of that is based in marketing and nothing else - two types of ED glass can have very different performance." I'm wondering if this change in nomenclature translates into a change in performance. Great product though.