Just came in today minus the Lens Hood ( on back order ) from B&H. I'm really liking this Lens! IS is rock solid, Focusing is lightning fast and I mean fast! Build quality is pretty good for plastic construction about the same as my 24-105L. The LCD Display is a nice and needed feature, shows Distant/ DOF, Focal Length and Image shake ( Not needed IMHO). The Focus and Zoom Ring is smooth and well damped. The Manual Focus is Electronically Controlled and the Focus does not extend or rotate like the v1 does. Has Manual Focus override in Auto Mode.
I had bought a Tamron 70-300 Di VC USD and that was a nice lens except the VC was a little herky jerky at times, then Lens was sharp from 70-200mm but above that it started to get soft and Auto Focus was a hit or miss so I returned it for the Canon. I'm glad I did, the Canon is so much better! Maybe I just got a funky copy as most reviewers were not getting the problems I did.
My copy of the Canon is really sharp from 70 up to 300mm. Here are some sample Images at 300mm at f/5.6, SOC, default settings in Camera and LR except Auto WB. Did I say the Auto was Fast? Yes it's fast, Accurate and light ( 710gr ) as compared to the 70-300L.
These are not artsy fartsy, just technical...............
IMAGE LINK: https://flic.kr/p/PU2SuC EF-70-300 IS II Test
IMAGE LINK: https://flic.kr/p/QsXHne EF-70-300 IS II Test_d
IMAGE LINK: https://flic.kr/p/QeWfu3 EF-70-300 IS II Test_b
IMAGE LINK: https://flic.kr/p/QeWcM9 EF-70-300 IS II Test_c