These are really two different animals. Both are nice knives and the Shun blue steel is perhaps my favorite Shun knife that they offer. The steel is good, the grinds are good and the handles are very nice. Price is good too.
The Masakagi is hand made in a small blacksmith shop. I love small artisans if you haven't figured this out by our selection so I always am attracted to this kind of knife over a knife made in a big factory. But that's just me.