I don't think this stuff should be used as DEER FENCING - I have no doubt a deer would run right through it. It's made to drape over shrubbery and trees to keep deer from eating the foliage - NOT for a fence to keep them out.
I have had mine up almost 6 months now and it's working great for the purpose I have it for - a cover to keep my chickens IN. I also am using it in my peacock pen and it works for them too - and they are much stronger flyers than the chickens.
Mine is fairly taut - not stretched, but I have taken up any slack with cable ties, to minimize the chance of a chicken getting caught up in it. No problems at all so far.
I don't think it would keep out a VERY strong and determined bird of prey, but it would deter them and slow them down. Same for something like a raccoon or possum. And a dog trying to jump the fence would probably go right through the neeting on the top.
I have 4' chain link fencing as the bottom part of the run, and the girls are secured in their coop at night...Plus, we aren't in a really 'high' predator area either... but we do have raccoons and possums and owls and hawks and I'm sure there are foxes in the woods too. So far so good...knocking on wood....