I think with Whose Line, if the comedians are funny, it's going to be good no matter what and the ones that are on the US version are quite good.

Most of the design shows and fashion ones are ok too, but these types of reality shows are different anyway. There's not really acting and plot involved as such. I've found that often, a remake of a drama or comedy where they've even used the same script, well then it all comes down to casting.