I ordered this one from Amazon, and it had cracks all over it. Do NOT recommend!

The Total Pond pond liners I got are amazing! They seem to be a little thinner, but man, they're tough!

You want to be really, really sure on your measurements though. I did an 8'x8', with differing depths (the bottom isn't flat, there are shallow and deep areas, and a hill going across part of it) and it needed a 20x20. The actual liner need was 15' x 19", I think. There was some overage, yeah, but better than seams, for sure.