My Yanmar came with a "LMC" brand box blade -- it was lightweight, 3 shanks and non-replaceable cutting edges (which were nearly perpendicular to the ground). It was fine for pulling loose material but did not dig very well.

Last weekend I picked up a King Kutter XB box blade.. 4 shanks, replaceable cutting edges, and the cutting edges are sharply angled. It's also a bit heavier than the LMC.

I love the XB.. been using it quite a bit the last few days. Sold my LMC a few days ago & made back just about what I paid for the XB.