For what it is worth, I am back from family holidays. Between friends and different families, four functions over three days. I took about 260 pictures. I just scrolled through them. I was wondering if the faster AF would have I benefit. I saw 1 image that was not tack sharp. Lots of in-focus eye lashes. Usually, with nieces running around, etc, I get a dozen or so out of focus, so, this is an improvement.

As for IQ, it is excellent. But, I am used to excellent with the 24-70 II. I think someone would have to put in some serious effort to identify a difference between these two lenses in terms of IQ. I did find the extra zoom range beneficial. I usually use the 24-70 II for family events and then add in the 70-200 f/2.8 II occasionally. Here I shot everything with the 24-105 f/2.8. I did occasionally want more reach, but it wasn't very often.

I took a few videos and the AF is now perfectly silent. I also photographed one of the host's house that was lit up for Christmas and dropping down to 0.4 sec exposure and getting a sharp image was nice.

The only "con" is the size/weight. The 24-70 II just handles and feels better. But, I suspect I'll get used to that.

Great lens. Doing exactly as you would expect. I can easily see this being a one lens solution for family events moving forward.