just get the cheaper one. If the floor does not have an underpad be sure to lay underlayment. 40 year warranty... who cares you will probably cange the floor 2 more times in that time span or will have moved
I've sold both in the past and do a lot more with Shaw than I ever did with Pergo. Pergo quality has suffered in recent years as well. Shaw has always stood behind their product exceptionally well in my experience.