I have a basement with fairly new carpet, and, since we just moved here the guess is two years old or so. It wasn't filthy, but the people we bought from had dogs, and so I'm sure there is pet dander in this carpet and it smells like dogs also. With my gym in this room, I'm breaking out in a slight rash every time I work out. It's not debilitating, just annoying.
Based on all I've read in here, I hired these guys, met Chris, saw what he did and the final analysis is that the carpet looks cleaner and smells better - and not so dog-like.
However, I'm still breaking out in that rash, so whether or not pet dander is something you can actually remove from carpet and underlying pad is still up for debate, regardless of what they are saying.
It's hard to tell from looking at the machine they use that it's doing all they say it does: disinfecting with one agent while dispersing, then simultaneously sucking up 225 degrees of hot, carbonated water. It seems like the carpet surface would be super hot, and wouldn't there be steam coming from the carpet if you had boiling water on it, particularly here on a cool, humid day?
With all that, I'll use them again for this room's carpet and our oriental rugs, because all said, I think this is probably better than shampooing. It's certainly not more expensive.