The CPVC pipe will stand more heat and pressure than PVC, so it would be the prefered plastic pipe.
IPS means Iron Pipe Size; which can come in Iron, Steel, Copper, Brass, Plastic, etc.
If you look at the connection points on the side of the valve you will see they have a bevel for use with flared copper; but it can also have a standard threaded fitting (IPS) used on it.
In Kentucky we can no longer use a female (threads on the inside) CPVC fitting because overtightening will crack the fitting. They have a neoprene seal in them but some guys like to use the wrenches and really crank down on it. We have a Brass/CPVC fitting now especially for that. It is made by Cresline Pipe Company and should be available there also.
Kentucky describes Plumbing as an art (among other things) and little things like this remind us of the Art aspect; otherwise it would be just a lot of BS.