Hello!
I stayed at both hotels in october, and I must say that Gran Porto Real is much more cosy and intimate than Royal Porto Real.But of course RPR is a bit more luxurious,and the room are nicer,but I thought the atmosphere at GPR was better.Very very nice hotel.At RPR you had to walk very long distances to get to anything(places) at the hotel.The restaurants at both hotels was great.You can eat at both places,I think.But in the end you will have a great time no matter wich hotel you choose.You only pay more for it at the RPR.Thats my experience,because I think both hotels where absolutely fantastic.
Enjoy your holiday.
Best regards from cold cold norway-girl:o)