I had not looked at this post in a while. I guess I should have stated that for my use and experience level with Photoshop selection tools, I have not found anything that works this well. As a landscape photographer, the use of the color selection process in CC I don't feel can come close. CC can never differentiate between all the various levels of blue in the sky, net, I always find problems. I am sure that others who are more experienced can do better.
I just find the LR implementation a lot more to my process flow. You can just keep clicking on the sky until the auto mask gets everything. No it's not perfect, as I still have some images where it just doesn't seem to work, but they are in the minority.
I tend to pull my tif files back to LR to work on them anyway, doing less in CC than ever before unless I want to run a filter and need a layer to blend. The toolset in LR including auto mask just work better for me, other examples, adjustment brush (without auto mask) ability to make WB adjustments in an adjustment mask (in LR) and selective color, and the gradient tool. I also would love to be able to click on a color in an image to make a selective color adjustment as Capture One allows.
I would love to see LR give you the ability to erase portion of the gradient mask like can be done in Capture one. It's my understanding this is already implemented in the latest version of Camera raw, but we are still waiting on LR 6 for it.
Paul