This has been my favorite lens to shoot with for years. The bokeh, sharpness, IS, everything is absolutely perfect. I always tell people, "You can't take a bad image with this lens." Well, recently, I purchased the 100-400 4.5-5.6 L IS MII. It's incredible, fast, sharp, etc. I enjoy shooting long. I haven't felt the need to use the 70-200 since getting this lens. the 100-400 shoots well in low light with little noise on the 5DM3.
Why should I keep the 70-200? I just see it sitting on my gear closet now.
Any comments?

