I feel the straps are inadequate. They are a single use item. I have used them and they have slipped more than once and I have ended up with my backside on the ground - not a crash and burn, just slipped down the tree. Now I use two 8 foot sections of climbing rope and simple boy scout knots to get the job done.
I guess if you are counting ounces then you'll be happy with them, they are light weight and compact and they hold the weight but if I had it to do again, I would not purchase them.