We keep the Sebo BS36
They are a cracking machine. The default choice for schools, cruise ships, offices, cleaning companies, and even Buckingham Palace, Clarence House and the White House.
Sebo have sold around 1.5 million
We use an ancient old trade in one in our workshop. It is abused daily. It still works.
As a commercial upright, or for any application where there are large expanses of floor, I can't think of anything better.