I went to Puerto Vallarta on my honeymoon, stayed there for a week. We had a great time at the resort, but when we ventured into the city... I was not impressed.
We did the usual tourist things like walking down town, visting local shops, eating some non-sketched out food. Swam with dolphins and did some zip-line tour, both were pretty cool. If you're okay with being relaxed and chilling at your resort, go there. Or if you want a taxi cab driver to give you the craziest ride of your life....
However, I voted Hawaii. I think you two would enjoy that more. I have never been, but had a friend live there for a couple months and it sounds awesome.