why do some radiators have inlets and exits on the same side and others on opposite sides, what are the advantages and disadvantages? i.e is it better to have inlet on top left and exit on bottom right, say for a pinto

its just to do with the inlets and outlets of the engine they're from isn't it?

eg rwd cars, radiator sits in from, inlet one side, outlet the other.

fwd inlet on the front of the engine, outlet at the back, and a pipe runs round the front of the engine, puts them on top of each other?

I guess it depends on the configuration and constraints imposed by the vehicle, along with whether it's vertical-flow or cross-flow, or even double-cross-flow (like the Polo)
Some cars have a full-width flitch panel on which to accommodate the rad, on others the rad has to be stuffed into a tighter space.
I guess a lot depends on the whim of the designer in many cases and why we have such a rich variety to choose from!
John.