I upgraded both my Macs from High Sierra (OS X 10.13.3) to Mojave (OS X 10.14) yesterday. Here’s my take.
Night mode: Meh.
Apps have to get user permission to access things like contacts: Yes!
I had to grant various access (half a dozen things so far) so apps would have access to things. Secure by default is the way to go for the operating system!
Screen shot tool: Yes! This is better for me than Greenshot for Mac because it auto-saves the file to my pre-defined location with less clicks. It’s still inferior to Greenshot for Windows — that lets me control whether it captures an area or a window using different hotkeys (saving me mouse actions) and it lets me define an area with two points rather than resizing an existing rectangle. But this still beats Greenshot for Mac and is really good! Best Mojave improvement for me after the security improvement mentioned above.