Puna represents a very diverse marketplace. Some much more interesting then other's, in terms of investment.
It is one of the most affordable districts in the State and is (was) the fastest growing district in the State.
Many sub-markets in Puna were very much bubble inflated and have come down extremely quickly. In many ways you would compare areas like Hawaiian Paradise Park and Orchid Land Estates (very large agriculture subdivisions) to places such as Las Vegas and Phoenix in terms of rise and deflation.
Over the last few months these markets for residential have shown some stabalization because the low price points have seemed to hit a plateau (activity and price).
The thing about the Big Island that you want to be aware of more then anything are lava zones. The reason for this is that we have a major rift zone in Puna that will and does affect the ability to get insurance for your homes (which in turns makes it hard for Buyer's to get mortgages).
That being said there seems to be a lot of activity in the overall Puna market as prices have fallen quickly, yet from the standpoint of affordability, there are not much places in Hawaii like Puna.