++1 and buying too...
I do already!
I would say that next to a porcelain pot/gaiwan a Hokujo is probably your best and safest investment if you are after getting the most out of your teas.
I say safe, because of course you could go for a Yixing, but with a Hokujo you know the clay is always good and the has the same properties. Yixing is a guessing game and one is probably going to dump money worth a multitude of Hokujos, before you find a pot that has the same properties. And you might never do so.