About the only reason you would choose the 500 would be if you needed a LAMS approved bike.
Hey Rose, don’t mind the boys sense of humour. (Good though)
odeta , as I have never had a chance to ride the 750 or the 500 HD's. I would say take both for a long test ride, both in heavy traffic & on an expressway & also in twisties. Just so you know how they will feel in all the conditions you might have to ride them in.