You are looking at different types fo machines.
The JD 430 is a garden tractor. (are you sure this is the right model #)
The NH TC21D is a small frame cut, 21hp with about 15 or 16 pto hp.
The Farm Pro 25 is larger/heavier than the NH but still modest in size, 25 hp, about 20 pto hp.
Hook a chain up to either the NH or the Farm Pro and they will pull the little JD around the yard like that thing is not even attached. No garden tractor can effectively compete with either the NH of FP.
The NH is generally considered a deluxe tractor, the fit and finish will be top notch, ergonomics on NH's are considered excellent, servicing dealers & parts network well established. Very likely the NH will have R4 tires.
The Farm Pro is a budget machine, fit and finish are below average, ergonomics are rudimentary, parts are generally available from many sources, dealers are typically independant operators. Very likely the FP will have R1 tires.
Now that said, the Farm Pro is going to out work (because of the greater HP) the smaller New Holland and likely cost far less but will probably be rougher running and less comfortable. So it boils down to what you WANT because both tractors will do what you NEED to do.