i recently used the 50 1.4 for a wedding i co-shot a week ago, along with my 100 macro and my 70-200 F4. the 1.4 really does get you some pretty good shots when the light gets low. i dont know how much difference it makes when you have the 2.8 zooms, but for me, my 100 failed half way thru and i was stuck with just the 50 and the F4 zoom and trust me, the 50 came in really handy when the f4 couldnt handle the low light. tho i have the 5dmk2, i still try to refrain from pushing the iso past 3200. for the price of the 1.4, if you're getting paid for the weddings, it shouldnt be too hard to justify. its really a valuable part of my kit.