And for your other question, check with pergo to see what they want for underlayment. I thought they just used this foam barrier and some use roofing felt for sound purposes. They have a web site.
Also maybe suzanne can enlighten us as to how long she had hers and how much longer she thinks she can put up with it before replacing it. I suppose it depends on how bad her scratches are.
Of course, even regular wood floors can be scratched and get water damage but they are refinishable at a cost.