I actually think that the orange 'Firefox' button was an important part of the browser's branding. Sure, it was blatantly stolen from Opera, but it meant you instantly could tell which browser someone was using. I think moving that functionality to the new menu button was a mistake, and it makes the browser look a lot more generic/Chrome-like (and is also against all existing windows conventions which says administrative functions should be in the top left).

But, in terms of day-to-day usage, its ___location doesn't really matter much.