it's always the same with reviews and comments: some people like a movie, and some people don't.
having said this, i count myself in with the ones who like this movie.
first, because robert downey jr is a very good actor (and here again: some people will agree, and others won't).
second, because it is a fairly original story. indeed: along traditional comedy lines, so the odd couple, the road trip aspect, the highly unrealistic adventures, the sexual connotations.... it's all there. but then there's more: the little unexpected things, these situations that put you completely on the wrong leg, the a-typical stuff.
third, because the humour really is good and the downey jr - galifianakis combination works as firecrackers (and you know what? as before: some people will not agree with this)
so for me it worked: i had an entertaining evening with good laughs and wasn't disappointed like with so many other comedies, thinking i could have spent my time better doing other things. fact.