I saw that movie on cable when I was 10 or so and it freaked me out big time. When I watched it again years later I couldn't believe I found it scary, but I had nightmares of those clowns after I first saw it. Same thing with the clown in the movie "It", I guess I just was really scared of clowns when I was young.
As for the masks, I'd say it depends how tall you are. The top one has a really long face and wouldn't look right on a shorter person, and the exact opposite for the lower one. IMO, if your 6' tall or more, get the top mask. Under 6' tall, get the lower one.