So far, so good...
I took a chance on this slip cover. The description reads that it will fit couches up to 96" long, and mine is 99". It fits! The exact dimensions of our couch are 99"x48"x31", and this slipcover fits perfectly in length, depth and height. It is very difficult to find a slipcover that will fit such a large sofa without paying hundreds for a custom cover.
I purchased it to protect our new couch from our new kitten. As other reviewers have mentioned it is quite thin. I'm hoping it will protect the couch from little claws jumping on and off, but time will tell. I will be putting a blanket across the back of the couch where the cat and dog spend the most time lounging.