I've had my steel sharpened and profiled by Elite a few times now, and it's excellent! Very consistent, sharp and the custom variations they have for profiling are my favorite by far. If I was in the Montreal area I wouldn't be using anything else.

I would guess the hole increases the blade rigidity by adding cross beams, similar to Tovi. But then it's called "Slingtech" and slings (slingshots) are generally are flexible........