Just bought Photo and I'm loving it.
For what it's worth, here is one of the biggest UX problems I've seen.
When I create a new Adjustments layer, I am not able to hit 'enter' 'return' or 'esc' to interact with the dialog.
'return' and 'esc' do work predictably when interacting with the live filters dialog.
In general, all these dialogs could use a little more clarity. Like the screenshot, one button in most dialogs often has an outline which signifies you can interact with it with return or space bar etc. As far as I can tell this outline doesnt mean anything.
It would be great if there was a visually clear default action, and a key to interact with it.
For example, 'enter' would submit and dismiss dialog. 'esc' may cancel. See default Mac dialog attached.