Really, you won't believe how light this thing is until you see it in the flesh and actually pick it up.
It's very nicely made (100% carbon fiber in the legs, and magnesium castings). It's solid as a rock, too. The base plate has a bubble level in it (moderately useful), and three set screws that push against your tripod head to make the head/tripod connection absolutely tight.
The 90 degree column rotation feature works very well. I haven't used it yet, but I'm guessing that it'll be quite useful for certain shots. You can get the tripod very low via the adjustable leg angles.
I use the tripod with a Manfrotto 488rc2. I think it's a very nice combination. Very light and very solid.
One more thing: this tripod is TALL, and that's a good thing. I'm 6'1", and with the legs extended, my Nikon D300 is right at eye level. Why is that good? Well, it means that for most (if not all) shots, I don't need to extend the center column. That makes the entire setup just that much more unshakeable.
400 bucks is quite a bit of money, but I think I got what I paid for.
P.S. I got Manfrotto's 055SPK2 spiked feet (Amazon). They have rubber feet with an extendable hardened aluminum spike in the middle. Very nice. If you get them, be careful during the install--you need to wedge the feet open so they slide onto the tripod legs without catching. A little water helps here too, and will evaporate when you're done.