I have never used foam insulation before and this was easy for me to use right out of the box. I had a 4'x8"x8" cavity in my basement that houses a waterline. When the previous homeowner installed this they put no insulation in at all and being that it's an exterior wall in the basement and I live in the Midwest that thing was pushing so much cold air in it was incredibly uncomfortable. Out of the box and job completed in about 5 minutes. Stopped all drafts and created a nice 2" barrier on the wall in which I will install some extra bat insulation over it. 4 stars because the spray isn't very good passed 6-8" from the surface. Make sure you can reach the surface you want to coat. Great for small jobs! https://www.youtube.com/watch?v=ggLAUsiuI_o&app=desktop
Air infiltration and exfiltration within a home contributes to almost 99% of moisture migration. Restricting air movement stops moisture accumulation so that the possibility of mold growth is less likely. Combined with a properly sized HVAC system, spray foam insulation helps control the indoor humidity levels to minimize moisture and condensation. Reducing moisture and controlling humidity can also add years to the life expectancy of a home, plus contribute to a healthier indoor environment. Finally, it also deters pests, making it difficult for them to nest. http://youtu.be/ggLAUsiuI_o
“It’s been scientifically proven that the temp of the shingles rises only a couple of degrees when there is an unvented attic compared to a vented attic,” said Garry Barlow, estimator at RetroFoam of Michigan. “If we lived in a southern state it has been proven that the longevity of the shingle did diminish by only one year. In the northern states there was no difference in the life span of the shingles.”
Good article, but it seems like you can chalk up almost all of those problems to the experience level of whomever is spraying the foam. Spray foam isn't an inherently bad product, but it's pretty easy to botch if the hired company is inexperienced. Fiberglass may be foolproof to install, but then again it has a terrible R-Value compared to a good spray foam. People just need to get referrals and do their homework whenever they research a spray foam contractor.
Thoroughly clean the roof surface. Roofs collect oils from asphalt, chimneys, and cars plus lots of dirt and dust. Coatings don’t stick well to any of these. We recommend cleaning with an inexpensive solution of TSP or TSP Substitute in a bucket of water (follow label instructions). Use a broom to scrub ponding areas and areas of peeling coatings. Work a section at a time and hose off the dirty water. Sweep away puddles to promote drying. Do not allow wash water to dry on walls, furniture, windows, and visible surfaces. 

Spray Foam Roof Insulation