I use it on my ceramic tile once a week or so...and it works great. However, it doesn't really get the grout any cleaner than any other mop. I also have found that the floor looks cleaner after it dries completely---for some reason. I do like the fact that not using chemicals means it doesn't have a residue to attract dirt--so it needs mopping less often.
I've never tried it on hardwood because I'm afraid it would damage them. However, my hardwood could use it...the "orange glo" mop kit only gets it so clean with two small kids.