As Rasmus said, the 711 is a more all around camp type "survival" blade, whereas the 1311 leans more toward the dedicated chopper/heavy machete side. That being said, the 1311 seems lighter than it is. 13.5 inch long 3/16 thick blade is surprisingly agile for it's size.

But if you can only get one for a do it all blade, go with the 711. I think you would be happier.