I agree with Safetymom, you cannot go wrong with either. I loved our stay at POR, the boat ride to DTD, the carriage rides, the lovely paths you can walk around and the southern charm all lend to romance. However, the lush tropical landscaping, pretty, charming buildings, the hammocks around the lake are also great for romance. I know last December my dh and I went to CBR for nine nights with our two kids. One night he and I stood on the bridge that connects Aruba and Jamaica with Old Port Royale and watched Illuminations, just the two of us while the kids were swimming (my kids are 11 and 13 and knew right where we were which was very close). I can tell you that in 15 years of marriage that was one romantic moment! We also laid in the hammocks one night while our kids played on the beach (again very nearby we could see them and hear them) looking up at the stars. Again, very nice romantic spot to enjoy with the one you love!
I would go with theming that appeals. Southern charm and a river or tropical lushness with a lake.