I thnk closed cell is a better product for the Northern States, but in hot humid climates
especially in hurricane zones I prefer the open cell product. Their are many open questions concerning long term effects of using closed cell when leaks occur. My experience through the hurricanes has been that the open cell foam (which is waterblown) gets wet and over a week to ten days after the damage completely dries out. I had several customers that had trees fall on their homes and exposed the open cell foam and there was no long term problems. Also, while most closed cell foam are R6.5-7.0 per inch and open cells are 3.5-4.0 per inch, R Value is just a matter of spraying the open cell thicker. Either way, I thnk for new costruction, spray foam is the best alternative.
In response to Nichters concern about holding water and causing mold and rot, most of the oepn cell foams are hydophobic. I have experienced the soy based foams not drying out and turning into a type of pea soup consistency when it gets wet, but that was about 5 years ago.
There are some applications that open cell should not be used in, namely in crawl space conditions where there could be mositure migration from the ground.