^ I like that the UI in W10M is denser, that fonts are generally smaller, and that font size is adjustable. That's great. Keyboard is even better than before. I struggle to find more positive things to say about the UI however. It does at least add a standard way to navigate between diverse parts of an app (hamburger menu), but I would have prefered an approach focused on providing the most innovate / streamlined / consistent solution for smartphones, rather than one focused on iOS and Android conformity.
I can see how some might find W10M's UI aesthetically more pleasing, but in terms of usability it has lost its elegance, consistency and flow.