A key difference between open and closed cell foam insulation is that closed cell acts like a vapor barrier. Open cell will pass moisture vapor.

With closed cell and batts with no other vapor barrier you may have water vapor buildup inside the walls in some temperature conditions, leading to mold.

I did open cell in 2x6 walls with a plastic vapor barrier on the inside then the drywall and love it.  5-1/2" of open cell is also a great sound barrier. Very quiet in the house.

Contractors don't like to use the open cell because there is more hand labor involved shaving the inside flush.

Closed cell has a higher R value per inch but open cell is always sprayed thicker to where total R value is about the same. Both fill cracks in an old home and cut off air leaks.  Use a separate can foam in cracks around windows etc. 

In my experience the vapor barrier and managing moisture is the key to an insulation job.

Jim at Dawn