When it first came out, Chrome was much, much more performant than Firefox, and had better standards compliance than Safari. It was just a better browsing experience. V8 was a big deal performance-wise.

Firefox has since largely caught-up from a performance perspective, although there is still some functionality inconvenience.

Of course the stated attitude toward the user is night and day - I switched back to Firefox about the same time they started integrating Gmail / Google accounts into Chrome.