I have both plastic and metal passenger cars. I don't do "passenger" very much, so my selection is modest. Plastic is wonderful stuff, but metal? Yeah. Wins every time. Cool to the touch. More mechanical.
Strictly a personal idiosyncratic thing, really.
You know, though - if we really want someone to offer a real set of "Heavyweights", we need to demand die-casting those babies. Zowie. May need to lay on more motive power.