Comparing vendors can get a bit touchy. I'd recommend that you first call them and ask what the source is for these parts. They may be different parts from different makers, thus possibly explaining the price difference.
Since front and rear floors do not show, the cheaper stuff may be just as good, although there's always the issue of "fit" and the extra hassle of trimming, if needed.
Maybe someone here can speak from experience with these parts from these vendors. You might also widen your search for other possible sources, gathering info on maker and price from more than two vendors. Many of the best sources advertise in HEALEY MARQUE magazine.