The reason I wouldn't use it is that it's a generic WC setup for the lazy. Yes, it looks pretty for an external unit, but I can build better myself. That's why I picked up the Uberradiator. The pump in that wouldn't power my system right, anyway. Plus, the choice of positioning for the res is questionable, if I'm reading it right. Putting the res after the pump output is an instant flowkiller.
I did look at one of these, but it just doesn't do the job for me, methinks. Besides, I'm not installing in a rack anymore, so the 19" constraint isn't there. I'll be building up from a homegrown McGuyver MCS that measures 30"Wx20"Hx20"D (
http://users.adelphia.net/~jnsholcomb/Page1.htm ). I'm just going to use stacked Enlight 7200 desktop cases (same effect, same benefits, 15% the cost overall, but not quite as supa-geek as the pure rackmount).