Like many people, I read through countless reviews and studied pages and pages of pictures tagged with Canon 24-70mm on Flickr, Smugmug etc before buying due to mixed reviews. But I bit the bullet and bought this beast to go with my 30D. I already had the 20mm f2.8, 28mm f1.8 and the 50mm f1.4, but i was tired of switching lenses at events, that and the 20mm F2.8 was crummy, but the other two were awesome lenses and I was afraid to part with them to finace the zoom but I'm glad I did.
Maybe I got a good copy?? But definately worthy of L quality, usually the widest aperature isn't quite usuable on most lenses (like my 20 f2,8 which was sharp starting at f6.3?!), but 2.8 on this lense is very sharp already, by 4 it's amazing. Focusing it super fast, Heavy but solid and balanced. Needs steadier hands to take shots, but that can be perfected with practice. Shots are contrasty and saturated, I love it!
It's not as sharp as my 50mm f1.4 was, but the colours are much nicer.