So I've been looking at getting a P mount for grad filters...Cokins grad filters are pretty inexpensive, but I'm curious about their grad ND. Some blurbs call them ND, and some call them grad gray filters. I've also heard that Cokin's "grad ND" filters are not really neutral...Cokin's website calls them gray, but some stores classify them as ND. If I were to pick one up, would they be so non-neutral that it'd be pretty noticeable, or are they relatively neutral? I'd like to not spend a ton of money, so the Cokin's are appealing, but if they will give crappy results, I guess I'll bite the bullet and move up to a true ND. What do you all think?