We vacationed in Oahu and Maui 7 or 8 years ago. It was great. I actually preferred Oahu. I like cities, and while the congestion was pretty bad, we were on vacation so it didn't really bother me. We drove around the entire island, and I found it to be really accessible and pretty diverse in terms of environment. We spent a couple of nights on the North shore.
Maui was great too. I threw out my back just because of the stress of driving on the road to Hana. It was a beautiful drive, but taking those single lane corners wasn't fun for me. The locals take those things with a crazy amount of speed and carelessness. The island also seemed to shut down pretty darn early.
I like pretty much every place I visit, and I like to research what it's like to live in those places. I found HI was going to be too expensive to maintain close to our lifestyle, have crazy traffic (2nd only to LA in my research) and with kids probably not the best environment for them to grow up in. What also blew my mind was the lack of people on their decks/patios in any of the apartment buildings.
I am pretty interested in other similar locales to split time when I retire. I'd love to spend a month or two a year enjoying island life to escape the snow.