You have to look at Chrome in more detail to see what they're doing behind the scenes. It stops bugged scripts from executing, it compares the scripts with the HTTP request headers to avoid cross-site scripting. Does Firefox do that? nope. And it's still pretty darn fast.
Then there's also incognito mode, which is extremely easy to use.
No browser is perfect, but Chrome is much closer to what a browser should do: browse and shut up.
Firefox may have more features, but it's so clunky that I can't bring myself to run it. The interface is horrendous and It greets me with these slow, annoying popup messages reminding me to do this, do that, test that.
Chrome does everything for you. While it still doesn't achieve full separation between processes, if something breaks, it's most likely not the browser --> refresh and you start over. Flash is always up to date, because which plugin do people use most often?
Even if the entire stack of processes crashes, it only takes a few seconds to bring them back, because Chrome starts fast.
No amount of features can defeat a usable and responsive interface. That's a feature!