As someone who has built countless pole barns and sheds. I can assure you the most obvious difference between steel and wood trusses is the amount of labor it takes to see it thru. Once you build with steel trusses, It’s unlikely you’ll want to use wood anymore. Wood trusses are labor intensive at the same time requiring more materials than a steel truss to do the same job. Hurricane clips and double headers with knee braces are necessary. You must cut and mark each header . If you have ever done it you know how much time it can take. You must cut and mark the 2×4 purlin. Tic toc.
Since the steel trusses sit on top of the post there is no need for headers or knee bracing. No need for hurricane clips, trusses bolt directly to the post.
Steel trusses are stronger and lighter than wood trusses. Example: 24′ deep building takes 13 wood trusses set every two feet. Therefore only three steel trusses are required for the entire barn using steel. True: a single steel truss is more expensive than a single wooden truss. Fact: you need up to four wood trusses for each steel truss. Wooden truss barns can have trusses spaced at the maximum 4′ on centers, some engineered and the design certified. Maximum spacing that can be used in agricultural barns, like HAY BARNS When using steel trusses: Typical spacing is 10′ if enclosed
or 12′ if the barn is to remain open.
Clips welded on top eliminates time consuming layout. Steel trusses come in two sections that bolt together in the center making transportation easy, saving time and eliminating potential mistakes.
In addition hungry termites, carpenter ants or bees can’t hurt steel trusses.
There will always be a place for wood trusses, I prefer cold hard steel.