If I had the opportunity to move to Hawaii, I would. Actually, the last time Mrs. Z-man and I were there (back in 2004), not a day went by when we didn't seriously discuss the possibility.
Hawaii is paradise - it is beautiful, safe (for the most part), but it is expensive. Just about everything has to be imported - stuff like groceries get really pricey. Real estate isn't too bad, but the daily costs are what will take a while to get used to.
The Big Island of Hawaii is not as touristy as Oahu or Maui - so that's a plus in my book. And the Big Island is one of the most diverse of the Islands in terms of scenery - from Mars like barren wilderness east of Hilo (Hawaii Volancoes National Park), to some tropical / resort type areas on the Kona side - you've got it all. Plus at night, you can see the red glow of Mona Loa - the active volcano. And for a month or two, there is actually snow skiing available on the top peaks!! Now how cool is that?!?
If they are offering to fly you down for an interview - I think you should take them up on the offer - and spend at least a week more on the Island to get a flavor of it, and see if you can get used to that lifestyle. And if you need an assistant (I don't know anything about what a design firm does - but I'm willing to learn!!) give me a call - I'll pack my bags tonight!
-Z-man.