
I have a Polti, but, other than using it for steralising things (eg. it is great around a bathroom, as there are attachments for toilet bowl cleaning etc - I used it multiple times last Jan when two of us in the house caught norovirus when hospital visiting!) I have found it pretty useless for actually removing visible dirt. In fact, about a month ago I gave up the struggle and bought a Vax carpet washer (which also does hard floors). This really does remove dirt! I have used it on carpet, rugs, porcelain tiles, kitchen floors and a sofa with very good results. Its downside is that it's a very heavy, bulky thing to move around (and store).
In the end, with cream carpets and a dog I had to get something that would use detergent to get the dirt out! I suspect if my (until now) secret wish list for an Airedale and a Saluki was granted, I would use that Vax every other week, and the steam cleaner once or twice a year.
I think it depends exactly why you want a steam cleaner - as a steam cleaner the Polti is a neat, straightforward thing to use. It does what it says on the tin, but I realised after buying one that it wasn't what I really needed.
Claire