I would try to find someone who has your specific model of car and find out how the fit is.
I've had the weathertec cargo trays and they hold up well, so the material is good.
They didn't make the liners for my Vibe, but I they did make floor mats.
The regular floor mats didn't hold up as well as the generic mats from the store, and the rear mats weren't made to fit my car, they were trim to fit just like you'd buy in the store.
A guy I know has the weather tec liners in his Cadillac and I don't like how high the sides come, they push away from the console into the foot well so the top can rub on your leg.
For my truck, I went with husky liner after I saw them in my buddies truck. I haven't had them as long as my weather tec stuff, but they seem pretty good so far.
I don't think there's a nickels worth of difference between the two.
I'd look for the one that best fits your vehicle.