A 232 transceiver will provide you with electro static discharge protection and the proper standard voltage levels,which increases noise immunity.This means you can have longer cable runs without drastic waveform degradation.Pc's have transceivers designed into them.If all you plan to do is connect pic to pc for experiments,don't use the transceiver.If your designing for robustness ,better to be safe than sorry.I always use the hardware uart to a transceiver,then dealing with inversions is never a question.