I've owned a lot of expensive glass in my day including probably 7 or 8 "L" lenses from Canon on my old 5D Mk II. (Which of course likely says FAR more about my credit card balance than it does about my skills as a photographer. We all know that owning great lenses no more makes you a great photographer than owning a stethoscope makes you a doctor! LOL!) I've owned the 70-200 F2.8L (and F4L) as well as the 24-70 F2.8L, 85mm f1.2L and others. IMHO the SINGLE MOST awe-inspiring lens I ever owned was the Canon 135mm F2L. I have missed THAT lens since the day I sold all my Canon full-frame gear. BUT... without doing any testing, my initial "off the cuff" impression of the Olympus 40-150 f2.8 Pro is that this is the first lens I've seen that instantly takes my breath away in the same fashion as my old 135mm f2.0L from several years back. STUNNING! I can't wait to put this lens out in the field but OH MY WORD I must confess I'm impressed!!!