Cleans up to baseboard. A fundamental fault with hot water extraction method is that many gallons of water are used which overwets the carpet. Even a good vacuum can do no more than leave the carpet excessively wet.
Hot water can be very detrimental to some carpet fibers.
Could cause color bleeding in some of the new multi-colored carpets. Shrinkage and browning are also potential dangers - and stain resist carpet can lose its stain resistance.