I use a steam mop on my tile and my wood floors. Only one floor do I have to do a little extra on the grout. That is the tile in the foyer. It always got muddy from the dog : (
I would sometimes spray a little bleach mix cleaner on the grout, let it sit a little and then steam on the heavy setting.

In general my grout in the bathroom gets clean well enough from the steam mop.

Debrak, I was surprised about your answer on 2 things.

1. Bleach on the grout has turned some grout yellow

2. Though I thought a steam mop would be good, I read today that it wasn't.

Do you have the 1/16-1/18" grout lines in foyer & bathroom with the rectified tiles? My DD used 1/16" grout lines with her ceramic by mistake and so now there is quite a bit of grout as you would expect.

The relatively new grout (about a year or so on the market) called Fusion Pro is supposed to eliminate age-old problems of grout maintenance. Because it is kind of new, it may be a good thing to be somewhat cautious about high expectations but a lot of professional tile guys (such as you will find on the John Bridge tile forum) seem to have high confidence. They say manufacturer has conducted lots of testing and they like what they see so far. Just something to consider as you investigate.

Well, I was posting when I was very tired and missed the part about rectified tile. Sorry. I have just regular tile and I just measured. The grout lines are just over a 1/4 inch.

There has been no yellowing or discoloration of the grout.

I'm sure with steam mops there is a lot of variables. I will say that I will hold it on certain spots and use it on the "scrub" setting. I does seem to push the dirt out. In our foyer we wish we had used a darker grout. We did use a good 25 year sealant which may be why it does clean up even when it gets.

I have 1/16 grout joints, regular non-sanded cement grout. My porcelain tile is light colored and so is the grout. So far I've had no need to wash the floor with anything other than water. I used two coats of a very good quality sealer (Miracle Porous Plus). IMO, non-sanded grout is easier to keep clean than sanded grout. The non-sanded is only for smaller grout joints, though.