Safari, by comparison, is just behind the curve on some developer-centric features. But Safari also has some things going in its favor: in my experience, it's the fastest browser on OS X by a pretty wide margin. Chrome is so bloated and full of garbage at this point that when I have it open, I usually have at least one tab sitting at 100% CPU (and this is with FlashBlock enabled). Safari also manages to feel faster while using significantly less power -- I suspect Apple has done some optimizations through Grand Central on this front.
Safari on mobile is a bit of a different story; yes it has problems, but I don't know that supporting a larger feature set is the answer.