I have a Bissell ProHeat Turbo and I like mine. If you read the instructions carefully and use it as directed, it should be pretty effective for the price. It sucks up much more dirt than just using a carpet cleaner, a brush, and some towels. Even an entry-level carpet/hot water extractor is 6 times the price of the Bissell unit, but a carpet extractor is going to deliver professional results while saving time.
I don't care much for the Heat feature as it only heats the cleaning solution up to a "warm" temperature but I love how my Little Green sucks up the dirt and cleaning solution nicely.
The key is to saturate the carpet with cleaning solution (whether you're using the on-board solution tank or a separate spray bottle), and then brush a lot, and suck as much liquid as you can. The unit will not suck up any dirt if it's the carpet is dry or just slightly damp....a liberal application of carpet cleaner and/or hot water must be performed.