A good graduated nd filter

I use the Cokin P system and use a mixture of Hitech (reverse grad) or Cokin ND grads. I've used mine with my sigma 10-20mm at 10mm but had to modify one of the olders. I basically cut away so I only had one filter holder and then filed down the plastic until smooth. I've bought the one filter holders (cokin) but they always seem to break so i've modified my own 3 fliter holder to make it into a filter holder which works betters.

Lee and Singh-Ray are better quality but I'm more than happy with my own setup of Cokin and Hitech.