All are free to use. So use them and decide which suits you best. There are several threads on this topic already. Do search before posting.
You really should stay away from all those other browsers and use the new Internet Explorer 9. There are many websites these copycat browsers still can't open. Mainly financial instituitons, like if you do online banking. These sites and most all other sites are developed to use Internet Explorer. I would never use anything but IE. And, IE9 is smokin' fast now. Just make sure you set it to GPU rendering in Advanced Properties.
I have firefox, chrome, opera and IE but I always use Firefox even though it sometimes lag. Chrome is a fast browser but I still prefer firefox because of the yahoo toolbar
I have use to 3 browser now ( opera , Firefox , IT 8 ) but i m always use many time to Firefox because its a working too good and faster .. Nikss