Difference ?
Might be a bit like the old joke--
Q-What is the difference between a vacuum cleaner and a home sanitation system?
A-About $500 dollars!
In many cases a household vac is good enough for commercial (church,motel,store,etc) use as is but there are differences.
With the above Elux upright changes included the name and label,longer,thicker cord(I think 3 wire)and spacer under upper cord hook to allow it to hold more cord,stronger bottom plate and I think 3 row brush instead of 2 row.There was a brochure for comm customers to promote the upright along with a tank (L or Special depending on year).
With other good vacs such as Hoover and Eureka colors and labels are changed along with longer cords,bigger cord hooks,stronger handles,choice of dirt cup or shake out bag,etc.