It depends. Cow meat is better when rare, pork is better well roasted.
A few pitmasters in Texas would like to have a word with you about over-generalizing....
Seriously though - a cow is a huge animal with many cuts. Some are better rare, some are sublime when cooked to a high enough heat to break down the collagen in it.
It is a bit shocking and I know a few people who just couldn't do it, we are so conditioned in the west to "rare chicken will kill you".
But, if you can manage it, very delicious. :)