I'm no insulation expert but I can tell you as a homeowner you can rent the machines that spray the insulation you wear a suit kind of like a painter. I've seen couple jobs with spray insulation and they were very happy with results afterwards. Regular batt insulation after years goes by tends to lose it's R value as instead staying in place they deflate if that makes sense. When I open up walls or ceilings to repair water damage I see this all the time. Where the spray on insulation wont do this.