I use the Tiffen Digital HT Grad ND filter and love it. Others probably use B&W or Hoya. Any way you go, a Grad ND is definitely handy and allows you use of your lens hood that other methods will not allow. Of course the trade off is that you have no control of the gradient vertically. Meaning that it will always end usually about mid frame. That can be troublesome if your intention is to include more landscape than sky as it will darken the horizon.

I think it has it's uses and I will most certainly always own one.