I had Weathertechs in one vehicle, and didn't care for them. Yes, they do contain dirt and water, but then the dirt is just loose, and rolling around until you get a chance to vacuum or shake them out. Then the vacuuming and shaking doesn't really get them clean, so you have to scrub them with the car wash soap and a brush. Plus, they are so annoying to walk on bare-footed. About the only plus I can see for them, is if you live in a very snowy or wet climate, and really need to be able to manage the water, they may be useful.
I really prefer carpet mats. At least when you get in, the dirt stays contained in the carpet, and stays put until you get around cleaning them. And even light colored ones seem to stay clean enough for me. About every few years, they need a good shampooing, and if that doesn't work, I just spend another $140 and get a fresh mat. My favorite are the Lloyd one-piece mats. I got them from "EuroCampers." I have always gotten my Lloyd mats from "California Car Cover" but they only seem to have the two-piece version. Just don't fall for the $110 Amazon version that has that cheap thinner-looking pile carpet.