I purchased the STM-500 to replace our mop. What a marvelous decision this was. I have a broken back and multiple surgeries. Mopping was a difficult chore. 
The steam mop is lightweight.  The design is very easy to maneuver when cleaning. I like that I can adjust the steam level for tile, wood, and carpet. The best part is that the steamer uses water and no nasty chemicals.
I recommend this steamer. I purchased it as a gift for my best friend in April.