I went with Armstrong because it requires no gluing. I tested Pergo and Armstrong and they came out the same. My test included dropping hammers from shoulder level (small dent...less damage than real wood, but can't sand it over), submerging overnight in water (fit to a dry piece the next day, and locked in without any difference in thickness) and scratched with a sharp key (slight marring). They both look great, last forever, seem impervious to water, and are super easy to install. You do lose the ability to refinish it, but the stuff should last 20+ years. Just pick your favorite color and the best price and go for it. I think Pergo makes a glueless version now also...that is really the way to go. Mine has been in two years now...looks great, no problems (two kids, but NO pets either).
hope that helps,
roy d