I GUESS the dry powder that Oreck uses is baking soda based. Seems to be a good concept.
One thing that I have learned about vacuuming carpets is that the carpet manufacturer should take a far bigger role in the design of the cleaning machine.
I THINK that some machines may be too hard on the carpet fabric, even too powerful...
But I know nothing of this Orbiter.

Earthworm - thank you for your response. Actually you have hit upon the one thing I didn't like about the orbiter. The carpet cleaning brush is very stiff and the brush rotates at a high speed as it goes across your carpet....I told my husband that I thought that the brush would eventually tear the fibers up.

I'm really in a quandry about cleaning the carpets...and I agree with you about manufacturers taking a bigger role in letting consumers know the best cleaning method.