I've had both. I like the coverage the WeatherTechs provide in the front, but the passenger side slides around a bit. The HuskyLiners have the grip teeth on the bottom to keep them in place, but don't provide as much coverage in the front of the footwell as the WeatherTechs. The third row HuskyLiners provide extra wrap-around coverage next to the rear doors while the WeatherTechs don't.
Overall, you can't go wrong with either of them. They're still better than the OEM floor mats. As for the center seat slider, you can't use it with any of the middle row mats since they cover the seat tracks.