I have a 2018 4Runner with the newer 4.0 and 5 speed auto. It power is acceptable, but it needs RPMs. I hear the 3.5 has less usable torque, and the transmission is always searching for the right gear for MPG.
I really wanted a new Tacoma but the engine/tranny and poor seat adjustments led me to getting a 4Runner. I also considered a Tundra, but I drive about 25K/year so mileage is important. I am getting around 20mpg with the 4Runner 4.0.