X.O.
I have a Hoover Floormate, which can be used to wash wood, tile & linoleum. I use it on all 3, from time to time. They do have grout scrubbing brushes (you change the heads from the regular ones), but I have not yet used them. I actually just use a hand-held scrub brush & grout cleaner when I want to get it bright white. I bought it about 3 years ago, and it was about $150.