Looking at the navbar, the horizontal and vertical alignment is all over the place, the search input has no placeholder or label, background colors are inconsistent, and paddings are just bizarre.
Not to mention the fact the extension ecosystem is still crippled. There's still no user-agent switcher, meaning there are sites I literally cannot access from my phone without installing an old version of Firefox Mobile or go back to using Dolphin Browser. "View Desktop Version" perversely still tells sites you're on a mobile browser.