San Mai theoretically should be able to take more bending stress.
I've read conflicting reports as to its actual make-up (as to steels used).
In comparing the two (standard vs San) in a short use (clearing a small plot of overgrown land), I found the most significant difference for me was that the San Mai didn't seem to vibrate as much, therefore less fatigue. This knife needs a longer handle of a different material, IMO.
It was a short use (a morning, including debrie removal), so I didn't really consider sharpness. Just swung away to see how they did.