As a parody I think it's good b/c it twists a serious, conventional, and conservative image (Neil Diamond) and makes it outré and perverse in a funny way.
what I mean is that parodies have to be judged within the qualities of the parody form. otherwise, it's like judging a piece of music by the qualities of, say, painting. A GREAT parody MUST use a previous image. if a parody DOESN'T use an original image, it FAILS. As a kid, I loved Wacky Packages, MAD, and Sat. Night Live, etc. Twisting an original thing is kewl in its own right.
Parodies by definition are not original in the same way that other art forms are since they can only exist in relation to the thing parodied and explicitly build on it. It becomes a matter of how clever or creative or biting that modification of the original thing is. With this poster, I'm ambivalent. It's a cliche'd idea but yet still a striking image graphically. So go figure...