American Lincoln OR Nilfisk are both worth a look, both companies make pretty decent machines.

We have a few sit on Lincoln machines on site, dont really get much bother with them, it does help if the operators are made to empty / clean them out after use / end of shift.

Depending on actual use it's just normally change filters / squeegee's & brushes for us, only really see the Lincoln engineer when there due a service.

Also have a couple of smaller walk along Nilfisk machines, never seen them in the workshop as they dont seem to ever go wrong.