Theora is not exactly mediocre, it just isn't the best.  But the "best" is expensive to license, and Theora is a reasonable substitute that is completely Free.<p>People complain about the extra CPU power it takes to decode Theora, but if I have to choose between paying extra for a more-powerful CPU or a patent license, I would choose the former.  At least I can make use of the more-powerful CPU when I'm not watching videos of cats flushing the toilet.