I think it might help to know what the application is: Walls, ceiling, retrofitting, etc... Also, what part of the country are you in (ie: what are the local codes)? Lastly, are you referring to open-cell or closed-cell foam?
Sprayed in place foam insulation is far better at providing insulation. it stops both convective, and conduction loss of heat.
Forgetting the convection for amoment, the R value alone is approximately twice tjhat of Blown in cells.
A fully installed foam insulation system will also include doing the ssills to control infiltration which feeds convective heat loss and drafts.
a closed cell foam functions better yet and does a better job aas a vapour barrier too.
The Q about what you meant mauynhave to do with cost vs value simnce foam is more expensive, but any customer I have ever had with the foam raves about all the benefits, one of which is sound proofing. a foam insulated hosue is far quieter than most.