AMD(ATi) has been running a raytracing system on their cards for a generation, too.

The plus is that raytracing accurately samples light flow, so multilayering (skin, plants, etc.), soft shadowing, etc., happens naturally by simulating real light situations. Will games get into it? Not for a while, because the problem is that as raytracing is very detailed, scaling for system performance will be a nightmare, where with OpenGL/Dx9/10/11 can simply turn off a feature to reduce graphics load. Raytracing has no features, it is simply simulating light.

I think the overclocking question is a little simple minded. If you want better performance without spending money, you OC, and this technological aspect will be no different.

As for price, the current generation of GPUs are already doing raytracing. I see little chance of an increase just because of this push for graphic accuracy.