Nico Nico Nii!~
I'm gonna be different and say that Safari for Windows is horrible because it's coded terribly and the windows have constant graphical errors, and that Chrome is very laggy in the video rendering realm, making it a distant second (and it seems to have had a fair few issues regarding Flash Player in the past couple of months). Opera's mouse gestures aren't even explained... they're just enabled by default, and that can be a pain at times, so that's third, simply because of user-friendliness. IE9 is easy to use, but because it's IE, it's horribly targeted by malware and the like, making it not terribly secure. Firefox isn't really any better than the rest, though. It's horribly sluggish because of its memory leaks and the like.
For perspective, I have to use a pool of browsers to get the things I do done because of each browser's disadvantages making it difficult to do certain things on each one.