Kevin,
Like I said, I haven't assembled the frames as of yet, but I will share with you why I went with Perka versus a standard metal building and other Perka look-a-likes.
Perka frames are metal web based frames that bolt together. Perka has a dozenish different frame designs that you can mix and match between. Perka can easily custom make frames for your design. I had them design a cantilevered 14' overhang for me.
I like Perka's insulation when compared to the bat fiberglass that everyone else uses.
I like that Perka uses wood for the girts and purlins. I will be finishing out the inside of my structure. This approach lets me attach to the girts that are already there. The use of wood for the purlins and girts does make the span between frames less when compared to a standard building.
hope this helps,
Mike