Spray foam or pink insulation?
If by pink insulation you mean fiberglass batts, both fiberglass and spray foam can be part of an effective insulated pole barn, garage, or shop. Color is not a performance rating. Compare the installed assembly, not just the material name.
Fiberglass is a fibrous insulation usually fitted into framed cavities. Spray foam is applied in place. The right choice depends on the available space, installation details, and the building's intended use. DOE Building Science Education: types of insulation
Air sealing matters with either option
Fiberglass insulation alone is not a complete air-sealing system. It needs a continuous air barrier with sealed seams and openings. Properly specified spray foam can combine insulation and air sealing, but the connections around doors, walls, and the roof still need attention. Neither material alone guarantees a dry, comfortable building. DOE Building Science Education: continuous air barriers
What should I compare in the quotes?
Ask both installers to price a complete wall and ceiling approach: insulation performance, air sealing, moisture-control details, and required interior coverings. Ask whether the foam is open-cell or closed-cell and have the designer confirm its suitability for the climate and assembly. Do not choose a foam thickness or vapor-control layer from a generic rule.
For a lined, conditioned shop, PFN's planning recommendation is to compare complete fiberglass and foam proposals before deciding either is automatically better. Spray foam's combined air-sealing role can be useful; fiberglass can also perform as part of a properly detailed enclosure. Actual installed prices need local quotes.
Installation and occupancy
Spray foam installation involves chemical exposure precautions. Ask the installer about ventilation, restricted access, and the manufacturer's re-entry instructions. Have the builder confirm required fire-protective coverings; do not assume exposed foam is acceptable. EPA's archived spray foam safety guidance
The next useful decision is whether you will heat or cool the building regularly. See Heating and Cooling for Pole Barns, Garages, and Shops.