I had one found it too heavy to use as a aggatation machine, although it did give a great scrub to the carpet.
I think they are designed for cleaning hard floors, the manufacture says they clean carpets just to add an extra string to its bow but I would not use it for LMC.
New they are too expensive for what we use them for and you could get something better for less money, but if you can pick one up second hand for a cheap price then go for it