Really nice I've been looking at getting a good strong ND filter myself, at the moment I'm stacking about 3 cheap cokin ND filters and it's a pain keeping them all clean A friend of mine uses a Hoya ND400 ( 9 stops ) and highly recommends it.
I don't have anything wide enough for this problem myself, but I have been toying with the idea of picking up a 10-24 ... I suppose I will end up with the same problem! Hadn't even considered that