Summary: I love this lens but boy howdy is it HEAVY. I just sold my Mark III due to its massive bulk, I traded down to a 6D, but when I add this lens I need two hands to navigate it. But...and this is why I bought it, we are talking SHARP.. We are talking FAST. I basically do available light shots, I almost never use flash and this lens is perfect for that.
Summary: I can't explain how much I adore this lens, and how worth the money it was. I own a 13 year old copy that still looks and functions like new. That's really saying something about the build quality of this lens. I you invest in this lens not only will you be taking your photography to a whole new level, but you will have a lens that will last you your whole career. The optics you'll see from this lens are just outstanding, something I can't get from any other.
Summary: Best lens I have! I have a few prime lenses and this is very sharp. Very heavy but that is not a n issue for me focusing is kind of slow but I use it for portraits so is not an issue. Can't go wrong. V2 is faster but more expensive. Can't go wrong with it.