Maybe I should reverse the question: Maybe say frame metal thickness (not a typical spec available for comparison, that I know of) is normally 1/4" steel (I do not know if this is the case) ... Are there any brands that use 3/16"? Or 5/16"?
You know, things like that. Materials or specs that aren't normally advertised or compared that make one brand a step above (or below) the others.
Or maybe ___ brand tends to use metal fenders, or a metal hood, whereas all the others use plastic.
Like my utility trailer. All (I think all anyway) utility trailers have fenders (until they rust off!), but the ones on mine are thick enough & welded enough that I can actually stand on them without bending them.