I have Findway in one car and WeatherTech in the other (WT fronts only). Findway are of lesser quality and the material absorbs and keeps some winter salt stain, despite multiple cleaning methods, while WeatherTech is easy to clean completely. The downside of course is the WeatherTech hard plastic, and on the passenger side there is nothing holding the 'tray' steady, which is annoying for the passenger getting in. Both are a substantial improvement over normal mats/winter rubber mats however!
Hadn't heard of Maxpider before, will have to check those out next time.