XRAY - Model racing cars

So I was wondering why I see so many people lately running the stock rear hubs with the ballstub going in sideways and not running the aluminum rear hubs with the ballstub coming in from the top. I have seen it from normal club racers but mostly also from all the team drivers lately. Can someone explain why they are not running the aluminum rear hubs and what the difference is between the two. also where you would run one or the other and the pros and cons.
Thanks

the plastic hubs will provide more rear traction.

alum will provide more rotation, a more stable and precise feel more and adjust-ability.

you could use either on any surface, it just depends what other compensations you have made in your setup. setup is ALL compensation, you can't improve any area without sacrificing from somewhere else, so it's important to understand what your car is doing well, what it could use more of, and what you can get away with less of. so you might see them using plastic rear hubs on carpet or astro and think why? well maybe they have stiffened up the rear so much with suspension, sway bars, etc that they like the way the car handles and does not traction roll, but they need just a tad more rear grip. just an example and a guess, but i doubt its far off.

thanks for the info. I figured it was that or something to do with more flex in the hubs being plastic and all. So if i understand this right if I use the plastic hubs I should have aalittle more rear end traction but the car might not rotate aswell because of the setup the hubs provide the car with. And if i have that right I guess I have to pic if I want to have more rear end traction or if I want the car to rotate more and get in and out of the corner faster. thanks again

On very high grip i use aluminum hub. When traction is going down i use graphite hubs.