well Jim Carrey was just making it big at the time due to In Living Color, so of course Ace Ventura was going to be a big hit...
as far as Ferrell goes...I liked a lot of his SNL work, but the only movie character I've liked is Frank Ricard...however, Anchorman is one quotable movie, regardless of it being stupid as hell.
I do think this movie has some promise, however.