What is the advantage of Rack and Pinion vs stock?

[abadsvt]

I was curious about the advantage of power rack and pinion vrs stock power steering. I have a powersteering setup on my truck now but i want don't want the truck to have "play" in the steering wheel. Unfortunately i wasn't able to drive the truck before i tore it apart so i don't know how the steering feels. Also if it helps with steering performance then that would be nice also. Thanks ahead of time.

Josh