Although I have not been to PV/NV - I think I can probably be right in saying there are more easily accessible activities off the Ko Olina property, compared to any Mexican property.
There are no issues of car rental in Hawaii as there are for (some) foreigners in Mexico (I would never rent a car in Mexico; I have no hesitation in renting a car in Hawaii) -so for Oahu, one has full independence in traversing any part of the island, at one's convenience, which is not likely the case for PV/NV or Mayan Riviera.
Secondly, I submit that there are lot of activities that one can partake of, in Honolulu - so even if one eliminated the relative convenience of getting to off-resort locations between the Mexican and Hawaii locations, I suspect that one would still have the ability to do a lot more in Oahu, then Mexico.
I do like Ko Olina. Its as good as it gets on Oahu, imo. The marina next door is very handy for a guy like me. For me, Ko Olina is a rental car destination as it is so far away from everything except the marina and the golf course.
The differences in resort quality are noticeable. The Mayan property is huge with a lazy river, wave pool, adult area pool, swim up bar, multiple restaurants, golf corse and resort activities daily. The rooms are more opulent with marble and tile floors instead of carpet. The veranda is huge compared to the maybe 20 sq ft verandas of a two bed unit at Ko Olina.
Getting from Ko Olina to Waikiki can take an hour in traffic. The traffic jams near Pearl City and Salt Lake are a definite turn off for me. If I have my way I stay on west side.
If you ever do explore the area near Nuevo Vallarta you would find that driving here is way easier than Oahu. Destinations near Nuevo Vallarta include a surfing town called Sayulita, a fishing town called Punta de Mita, a tourist town called Bucerias and a large city called Puerto Vallarta. All of these are easy drives from NV.
I have never had a rental car issue in Mexico and I rent a car for at least 3 weeks in Mexico every year.
Both destinations are great. I like them both but would rather head to NV over west side Oahu given the choice.
Activities are easy in NV. Check out Vallarta Adventures. The extreme zip line is a blast. Whale watching is up close in Mexico compared with a 200 ft buffer in Hawaii. We had a whale lift our zodiac and spray us. These guys are located in Nuevo Vallarta and do include transportation to their facility.
http://www.vallarta-adventures.com/
The only thing going on in Ko Olina is Paradise Cove which is really hokie compared to the Rhythms of the Night.
Anyway, I am in no way bashing Ko Olina, just pointing out differences.
Bill