Adblock is the one thing I think FireFox has over Opera.
But Opera 8 Beta 3 is the only thing I run now. FireFox kept pissing me the hell off. For some reason, sometimes when I try to copy text from in-line tables, it will ... either not copy the right area, or it will REMOVE (stop displaying) the text I was trying to click, or it will select the entire page... and so on. That just pissed me off, and because I had no idea why it was doing that or how I could avoid it, I just threw it out and back to Opera 8 Beta 3, which is where I keep my mail too. Opera M2 kicks my ass.