Ass all have said depends..
I went with wood frame for multiple reasons;
Matches the character of my house
Type of tools/equipment required to construct
familiarity of construction process
cost to finish interior
insulation cost
potential future conversion to a residence - never know I may get tired of playing with cars
All vinyl /Aluminum exterior

that was my decision process anyways...

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'01 P1500, Blown/Inj BAE,/Veney ,Bruno/CS2,Dana 60
'01 Dodge 3500 S Cummins Auto, Fresh air kit, 4" Exhaust,
'05 Dodge Magnum R/T - Too Much to list
'60 Willys CJ5
'01 International LPX - Project,DT466, Allison
'64 Plymouth Valiant, Inj 528 Hemi, 2spd