I do hate how ... sneaky they can be though - on Opera Mobile every so often I'll find a bunch of shit added to my speed dial. :@
Which also reminds me of Adblock Plus recently - it keeps updating, flashing up a stupid tab, and re-enabling the "Google are forcing us to allow their ads" option, with no way to stop it. :@
Chrome/ium's UI is shit, but less contrived than what Firefox does.
It's faster to startup, and a bit lighter weight - though a huge chunk of that is faked, which makes it a pain when things are actually running slowly. And having task manager spammed with processes is a pain.
Also is/was less effort to configure multiple instances - even though they're not really separate instances and interfere with each other except in the places you actually want them to.
For everything else I currently can think of, Chromium is equally or more shit compared to Firefox, and if I didn't open and close assorted browser sessions so often I'd probably ditch it. :/
The right way for Mozilla to respond ... well there's a thing Linus said about Git - any time he was unsure how to implement something, he'd look at SVN and do the opposite. Mozilla need to do that with Firefox, instead of aiming to be a poor imitation of Chrome.