Have the Haan. Love it! However, I have light beige grout (soooo wrong!!) and use a "scrubber" made by bissell for hard floors and tile. Love this one too as I feel it cleans even better- I can see the water it sucks up.
But, I end up on my hands and knees with magic erasers or clorox pens (really work). I just bought a grout brush. $1.75 at Dollar General. Going to see if this works. Seriously thinking of staining the grout to a tan so I don't have to do this all the time.