I reckon rotary is the go, but then you get this issue
that said i dont know why this vid has that screaming wail. my pump is external on my HX machine and it is quieter than a sunbeam 6900 anyway and it is sitting out on the kitchen bench (the rotary pump) the wail must be the opv valve or something?
but you can see the size of it
its a size thing and $$$ for small machines i think, they just dont fit and cost 400+. And a rotary maybe has a better life span in a commercial environment?
this is a can o worm / piece of string question it all depends on your usage and preference