Glass or resin?

I was in the market about a month ago for some ND and GND filters. I am thinking about studying this wonderful art form - lanscape photography. While at the store, the sales associate told me that the Cokin resin filter system does not come close to achieving results as beautiful as screw-on glass filters.
What are your opinions? Since I have been in this hobby, a little over a year-and-a-half now , I have found that some sales associates do not know what they are talking about (i.e. one guy, the owner of a business, blew compressed air into my 20D; it is now at Canon trying to be cleaned properly ).

Hey

I'm pretty new to photography too and on a tight-ish budget so I have cokin filters and they seem OK to me but then I have never used Lee or some of the more expensive makes.

I like the cokin way better than the screw on, especially with the GND because you can move it up and down, it is not fixed in the middle of the image.

Some people here on the forum like the Cokin system but, they use Hitech filters with them and are of higher standard of quality. Some use the Cokin GND and some do like them. If your budget allows it, go for the best and get the Lee filter setup.

I use the Cokin holder with the hi-tech filters. I'm quite happy with that set-up. If I win the lotto, maybe I'll go for the Lee system!

Idiots!

Do a search in the Accessories & Storage section. I did some reading about a month ago. I don't think the screw-on filters are held in high regard. The square type allow you to move up & down to find the correct position.

I don't have any yet, but this is what I read