Carbonated/Buffer (Chem-Dry): Often accused of 'fear marketing'. Their traditional method supposedly doesn't really extract the dirt from the carpet/house and their buffers wear carpet down. Many complaints that carpet is extremely stiff after cleaning. They have apparently begun switching to a truck based extraction system (hot water extraction, but 'carbonated'?) that may work better. But can they be trusted?

Hot water extraction (Stanley Steamer, COIT, etc.): Perhaps best for extracting dirt. Numerous concerns that if not done properly that high amount of moisture left in carpet & pad can cause mold/mildew growth and faster deterioration of backing and pad. Some/many do use perc, hydrogen peroxide, and other not too appealing chemicals?

Other options? Independent cleaners better than franchise chains such as the 3 above? Any websites with an honest comparison of methods and who provides them?

I found an excellent, local independent in an ad in a local home magazine. I used 4 independent companies over the years, all with the same type of equipment, but one did a superior job because their technicians were so thorough. They also moved and replaced all the furniture, with plastic underneath. I gave them a big tip.

I make it a point to schedule cleaning on the warmest, driest day possible. On cold rainy days, the carpet is just not going to dry, even if they extracted as thoroughly as possible. Also, we have a commercial blower, and running that in the room speeds drying ENORMOUSLY.

Recently, a company that did some flood restoration for us has been sending me mail piece about their new "residue-free" carpet cleaning. If I were still getting carpets cleaned, I'd look into that. (However, I'm now about to replace most carpet with wood and cork flooring.)

Oh, one more thing. If you have pets, and examine your carpet at night in the dark with a blacklight, well, first of all, you'll be ready to get rid of your pets no matter how much you love them! Really, you'll see accidents you never knew happened. Each spot you can see on the carpet is like the top of a pyramid that has soaked into the padding below in a much larger area. If I were keeping my carpet, I'd pretreat all these areas with oxygen bleach and enzyme cleaner, pulling the carpet up from the tack strips to get at the padding. Then I'd have the cleaners finish up with their process. You can have them restretch the carpet to the tack strips if you don't want to do it yourself. Or, at the very least, mark the accident areas you find with the blacklight so they can at least treat them with their pet stain formula.

Next time around? I bought a carpet steamer. It cost less than HALF what I paid her. There are no-scent, no-dye cleaners you can get for the steamer. I used HALF the amount of cleaner recommended (which I almost always do with any kind of cleaner--manufacturers always tell you to use too much, just to sell more product). My rugs were actually cleaner, and stayed cleaner longer than when the pro did them, and it's not that much work. An added benefit is that if you do them yourself, you can split the cleaning up, so you can still walk around at least part of the house, while the other part is drying.

Don't think I'd ever go back to having an expensive pro job now that I have the steamer--I can do a better job, and a minute fraction of the cost, and I sort of enjoy doing it.

Fear marketing :
Don't know where that comes from, fact is, we will point out the advantages of our process vs. the traditional steam cleaning.
Our process uses much less water/cleaning solution than the traditional steam cleaning process, most carpets will be dry in 2-3 hrs.
Before I went into business as a ChemDry franchisee, not knowing any better, I had the carpets in my home cleaned twice, by 2 of the big names in steam cleaning, both times the drying times were well over 8 hrs.
Now, when I clean them myself, they are dry after 2hrs.
They also will stay clean longer, since our cleaning solution, the Natural, does not leav any residue in the carpet.
Some of the steam cleaners use plain detergent for their cleaning, this will leav a soapy residue on the carpets, which is actually dirt-attracting, causing quicker re-soiling.

Reappearing spots :
This is a problem mostly associated with the steam cleaning process. Because the steamcleaning process leaves so much more moisture in the carpet, but at the same time does not clean as deep, spots and stains will at first be gone, but later re-appear, this is called "wicking".
This is a problem the ChemDry process does not have. I even give my customers a guarantee, if any spots come back, so do I, free of charge to take care of it.
In my 7 years as a ChemDry franchise, I had to go back once !

Do-it yourself cleaning :
Sorry but the statement that a do-it-yourself machine, be it Rug Doctor, Bisell, or whatever, will do a better cleaning than a professional cleaner, especially a ChemDry cleaner is just plain ridiculous.
These machines don't even come close to the heat and suction generated by professional equipment, and therefore the cleaning is superficial at best.
If you have very lightly soiled carpet, yes, they might work, but on dirty carpets, they don't come close to professional equipment.
On this one, I also am speaking from pwersonal experience, I also tried one of those, if I remember correctly, it was a Bissell, the results were disappointing, total waste of time & money.

But don't take my word for it, give it a try.
You can find the local franchise in your area by going to www.chemdry.com, there is a localizer function, you put in your zip code, and it will show the franchises in your area.

Have never used any of the "steam cleaner" companies, so I can't comment on them. I do have an Oreck carpet cleaner for cleaning up smaller messes, and it works ok, but not as well as professional cleaning, obviously.