I know a bunch of people who use DE and are happy with it. My understanding from the vet is that it is VERY important to remove fleas from the environment as well as killing them on the dog.
We've never had a flea problem, but must have brought some back from our trip down south, despite putting Advantix on Kodi just before we left home. The vet suggested this site for the best information on flea control:
Then I found Sentry Natural Defense Flea and Tick Carpet Powder at our local Petco:
This is a carpet flea powder that uses only natural botanicals. (I noticed they also have products to put on your animal, but I haven't tried them)
I put the spot-type flea stuff on the cat, but it was too soon to put it on Kodi again. So I washed him THOROUGHLY, using LOTS of soap to kill the fleas on him. Then I washed ALL his bedding, plus the bedding on our bed (because he cuddles with us there even though he sleeps in his crate) in the hottest cycle in my washing machine, to kill the eggs. Then I used the carpet powder EVERYWHERE, as directed. You sprinkle it onto carpets and upholstered furniture, rub it in, wait at least an hour, but 24 hours is best, then vacuum.
It worked completely with just one treatment, and it doesn't smell chemically at all. Just smells strongly of cinnamon and clove. Also, it's safe for pets and kids, so I didn't have to board our bird for the duration, which we've had to do for ant treatments in the past.
Not sure if this would work in areas that have really nasty fleas, like down south, but up here, where we were just dealing with "imported" fleas, this process seemed to do the trick!