I have been using the 24-105L lens for many years of pro photography. I decided to take the leap and buy a 24-70L mk2 recently so I could shoot more often at f2.8 for better bokeh. The lens I have is just not that sharp compared to my old one...also exhibits a lot more flare. Once in a while I get a really sharp image, but most often, just so-so. I also use the 70-200f4 L, which is just great and the the 35 f2 is and the 85 1.8...all on 6d bodies.