I have to say that Im pretty impressed! Ive never owned a carpet cleaner – nor had my carpets cleaned. I was going to get them professionally done but after reading consumer reports study on carpet cleaning I decided to spend a little more and buy a machine I can use multiple times. (this machine cost at most $50 more than having your carpet professionally cleaned one time) Now, my carpet is all dark green so I can speak for how it would do on carpet that really shows stains…but my carpet is old and who knows if the owners before us ever cleaned it…but it definitely picked up an incredible amount of dirt! I did my whole house (probably 1200 sq ft of carpet) on three fill ups…with some left over…it didnt take too long and it dried within an hour. If youre considering buying a carpet cleaner – I definitely recomend this one.
Also…I recommend actually sitting down and reading the 6 step set-up guide…I hate reading directions but theyre simple (with pictures) and necessary so your machine doesnt leak. It took maybe 10 min to put together reading the directions! 
Who knows how long this machine will last me…but with at least one more use I would feel COMPLETELY justified in purchasing.
The ONLY reason i gave it 4 stars and not 5 stars is because I have no basis for comparison…