It really depends on what you want to spend and how well you want it to work. I used to review floor care products, when you get to use machines side by side, you quickly see just how bad the bad is and how good the good is. IMHO, it is a complete waste of money to buy consumer level products, such as Bissell or Hoover or Shark, when for the same money you can get professional quality and performance in the likes of Rug Doctor.
If you want cheap, speed, and the appearance of clean, then you'll be more than happy whatever consumer grade machine you choose. If you want something that actually cleans, that actually does what you bought the machine for, then you need to step into the class of machine capable of delivering that level of performance.
Topically, the "cheap" machines are operated like a vacuum cleaner, they're lightweight and low on suction, which makes them extremely easy to use, but not so effective at cleaning, deep cleaning, or extraction of the cleaning agents or rinse water. More capable machines tend to be dragged backwards, this is because their suction is strong enough and the machine is heavy enough that it couldn't be used any other way. It is the extreme suction and the weight pushing the head into the carpet fibers that removes the water.
Now on to pricing. Both Bissell and Hoover have machines that start at about $100 and increase by $100 as you "step up" in machine, unfortunately, their $100 machine works just as poorly as their $300 machine, or visa versa, however you want to look at it. Bissell's $400 Big Green machine supposedly rivals a Rug Doctor Pro, which is currently only $321 on Amazon. I'm going to be honest here, I've not used the Bissell Big Green, but I have used a number of their "lesser" models and am completely unimpressed, and find it hard to believe that once you step up to the $400 mark that they suddenly have something that works.
I have extensively used a Rug Doctor Pro and it hands down, out cleans any Bissell or Hoover product. Bissell and Hoover are great at cleaning carpets that aren't dirty or stained. They will remove light soiling, maybe lighten stains a little bit, that's about it. If you have serious dirt and stains, or worn carpet, then you need a machine that has the ability to work the fiber and, more importantly, extract the cleaning materials. My money is on a Rug Doctor.
Back when I was doing reviews, the RD Pro, that was the "base" model that RD was producing at the time. They have since come out with a Rug Doctor Deep Carpet Cleaner, which is a smaller model designed to directly compete with the consumer brands. I've not had the opportunity to try one out . . . yet . . . but would expect it to still run circles around the competition.
Stepping away from the conversation of carpet cleaners for a moment, I am someone who wants to use well designed tools, that are built to last, and have a look and feel of quality. Using tools like this is a complete joy, making the "work" not seem so much like work, never worrying if I'll be able to do what I set out to do, or suffer the frustrations and hazards of using inferior tools. it doesn't matter if we're talking about automotive tools, construction tools, vehicles, you name it, the quality of the tool defines the experience. The more a tool gets used, the more important that that tool be beyond capable of the job. So, why would I buy a Walmart or Harbor Freight special, when Mac, Snap-On, DeWalt, or Milwaukee is better suited to the job and give me the experience I'm looking for? Taking this same mindset to carpet cleaners, I'll take a Rug Doctor over anything else for the price.
I'd be happy to provide links to the carpet cleaner reviews I've done upon request. I'm not posting them here and now because self promotion was not the point of this post.
