There's only two things I don't like about the GX. One is the fuel economy. The other is the side-swinging rear door. I much prefer top-hinged doors as they make great ways to duck out of snow or rain when at trailheads.
In the three mentioned in the title, I'd either go Lexus or Toyota. The Highlander is a crossover and will be more car-like than the Lexus GX, but less luxurious and has no 4x4 system if that's at all important. When we looked at the 2nd Gen Highlander vs the GX470, the missus preferred driving the Highlander and being a passenger in the Lexus.
