The Boss Street is heavier, and the stock is thicker. .22" if I remember correctly.
While S35VN is not a bad steel by any means, I prefer fixed blades to made of very tough steels. INFI is at the top of the pack.
It also depends on what you are going to be using it for. If you want a knife to baton with, abuse, and that is virtually indestructable, then you want to go with the Boss Street. If you want your knife to cut better, the Nyala would probably be a better choice. In fact, a Bark River knife might be a better option if you wanted more of a slicer.