Personally, if blood is actually done well in anime, it's better, but for my favorite manga, I like the blood in the manga better. (Not that there is a ton of blood in Eyeshield21, but there is a bit. Hehe... stuff for the rapid fangirls:
dramallama Hiruma after getting chopped into the ground:
Eh... I'll find it later. *lazy*
Hiruma after getting punched by *gasp* Musashi!
HereEh... The image is resized, so it's a bit small. Hm, this one doesn't have blood, though.