I agree with the sibling comment; I think Chrome's solution is terrible. If you have a lot of tabs open from the same website (i.e. with the same favicon), then finding the right tab becomes really tedious. And, even if all the favicons are different, I don't necessarily remember which favicon corresponds to which page.

I can't really compare this with Firefox's native solution though, because I use Sidebery (and I used tree-style tabs before that).