Yes, only 2 stars, although it cleans carpets very well. (I've never tried to climb stairs) So why 2 stars? We have a lot of carpets in our house, so I've used several carpet cleaners (Hoover, Bissell, etc.). It just didn't have the features I needed. The 3 cons below, which are not present in any of the other machines I have used, combined were the deciding factor for me. If I have to do a little patch at the top, do I have to stop [and refill or not? I can't say with that. 2- To drain the solution you need to tip it on its side and shake vigorously. Very cumbersome and maybe annoying for some. 3- Carpets have become significantly damper than in other machines. I've been to Southwest and other machines and got the carpet dry in just 2-3 hours. However, with only 2 cleaning cycles and 3 drying cycles, the carpet took more than 6 hours to dry. Looking at the sensor through the glass of the dome filter, I got the impression that it wasn't picking up as much as my other purifiers. The "extended" drying time indicates this. If you don't care when it dries, are strong enough to hand de-drain and can wait a few hours for your carpet to dry, I would recommend this machine. But I haven't had these disadvantages with any other $400 machine. Needless to say, you get it with Revain's 30-day money back guarantee. Like a great car to drive but without a fuel gauge, a special lift is required to drain the oil and it needs to be left to dry overnight after washing. jmho