you guys should check out the kitchen forum in knifeforums.com
there are two or three guys there that know more about Japanese knives than anyone I've ever met.
It helps that one guy owns his own shop. The other two...well, they have no other excuse than being downright obsessed.
FWIW, the Kasumi and the Shun knife are almost identical. They are not however, made in the same factory. I don't think you could go wrong buying either one.
I personally LOVE the way the shuns feel and look. I'm not too sure about the fatigue of the Shun though...the handle isn't THAT small...and it is a perfectly balanced blade. I couldn't recommend it more highly.
Depending on how much you want to spend, there are always other brands.
Japanesechefsknife.com or the knifeoutlet.com are great places to get good blades for decent prices. The previous site has high end knives that will have any chef/aspiring chef DROOL with envy.
It really puts western steel to shame, as you can imagine the men making the knives come from a long heritage of samurai sword makers.