My 12 Mil solar cover from In the Swim (aka Save On Pool Supplies) which has a 7 year warranty (2 Years Full) completely failed after only 12 months. The side exposed to the sun deteriorated to the point where thousands of little blue dots were everywhere. Needless to say I was not happy with this, but they may have redeemed themselves with their warranty process.
The warranty states that the customer is responsible for returning the cover, but I was pleasantly surprised that they only require a 2'x2' section to be returned. About a week after sending them a small piece of the old cover, I received a new cover.
So I am not thrilled that the cover fell apart so quickly, but at least they stand behind their product.