I agree, these UI changes are practically unnoticeable except the menu changes. I would like more contrast for the address bar, though.
Not only don't the "tabs" look like tabs anymore, it's also very difficult to tell which one is actually selected, which can be very annoying depending on how you use tabs.
How is a bunch of page-select buttons on a bar an improvement on a design where they actually look like tabs?
Edit: Actually, the lack of visual feedback on which "tab bar" button corresponds to the current page (i.e is the current tab) is likely annoying for most users, since you need to know in order to close that tab rather than some other one by mistake. Best bet to be sure is to click on the tab button you think is the current one, to reselect it, before clicking again on the "x" to close it.
I couldn't even tell which tabs were selected before this update, which is really frustrating if you have over 400+ tabs open. I realise it is excessive, and would appreciate a solution other than Tree style, Session management, Tab suspender add-ons/options to manage everything 'smarter' and also limit the fingerprinting at the same time.
Anyways, from my limited usage of the new version, I am glad that the container accents are now shown at the top, and tabs playing audio have more focus.