Well, you are at 2 very different price points and knives! The Artifex is stainless with a Western style handle. The Moritaka is Carbon with a Wa style handle. The Artifex will take and hold an edge very well, same with the Moritaka. Maybe look into a Richmond 210mm laser? AEB-L steel and a thinner grind. Also, check out Konosuke knives for very thin, very sharp knives. White #2 or the HD (semi stainless) series would work.
I have one of these in 240mm and love it! Very thin behind the edge, I've stropped it twice in the several weeks I used it on an uncoated denim hard strop and the edge has popped back to very sharp levels. It's a little heavier/thicker, but cuts wonderfully and has a nice convex grind.http://www.chefknivestogo.com/tanakagyuto2.html