I own the F5915-900, and also looked at the F5914-900 on "another retailer's" web site. Based on the other retailer's description of the product, I cannot see any differences between the two models. Perhaps Hoover made one tiny change, and then gave the new model a new number. Oh, and the other place is charging about $30 more for the other model.

I have two inside dogs and there have been some accidents. I think it did a great job of cleaning the stains and removing the odor.

Have you tried Hoover's site? Just a thought. I think I'll be looking for that too, I'd like to use it on my hard surfaces if possible.

I first used the solution that came with it, but once that was gone, I did a solution of water, vinegar, and a bit of laundry detergent (just make sure it doesn't have bleach in it!). Also you can use any brand of steam cleaner detergent (Bissell, Rug Doctor, Resolve, etc) you want to as well, it's still going to be just 5ounces of cleaner per tank for those too. Just make sure you do a color fast test for whatever you use, so that you know it won't effect your carpet. I usually do mine in a corner, or in a closet :)

It came with an upholstery attachment.

I have used it on Berber and it worked great! I am very happy with it.

Yes. The only thing I didn't like was the excess water. Be cautious...

No, you don't have to use a cleaning solution; I use either plain water to rise, or a slight bleach solution for sanitizing/deodorizing. However, the chemicals aren't that bad and will give you maximum results. I am cautious about this also, because I have a small breed puppy. There are lots of brands on the market compatible, even mild ones.

VBry:
I too have been looking at both models. So far all I can tell is that the F5914900 has a 3 foot longer cord and has a turbo tool. I haven't actually looked at the box for F5914900 yet, so it may have turbo. It seems that the 5915 would be a newer model considering the number sequence. I'm going to Wal-Mart tonight to look at the box. Will update if I find out anything new.

If you contact Hoover or look in your book it will of course say Hoover cleaner should be used. There are many other cleaners you can use in that will not harm the machine. I do recommend Hoover shampoo because it works well. When you are adding any soap to any machine NEVER USE MORE THEN IS RECOMMEND infact use a little less. If you do use more, soap will build up and instead of making the carpet clean it will make the carpet get dirty quicker. It is also recommend by some vacuum shops that you use clean water to rinse the carpet after you clean it. It is a little more work but it will help your carpet stay clean for longer periods of time.