I did a quick search and found that some people don't like it because the sky/scene is unevenly polarized when you're using a wide angle lens. Here's the link-
http://www.luminous-landscape.com/tu...larizers.shtml
That link goes on to say that if you like the effect you should just use one. Be careful though because some polarizers are not made for the wide angle and thus are too thick. So when you put them on it will vignette quite a bit. There's another thing too but it's too complicated to explain so I'm not going to bother.