Originally Posted by Turnaround
To elaborate - the idea of a ramp is that it makes the area under the strings feel consistent whether you are fingering over the pickups or not. With the ramp in place you cannot dig in as hard and so your plucking is more consistent regardless of where you pluck. So really, they don't actually "do" anything. They just sit there and feel different.
Should you have one? Sure. Or not. Personal preference.