I've used the Rotobrush and the Goodway system and the Ram Air. Ram Air is defitiely the best of the three. It gets a lot more dust out of the duct work, does not hang-up inside the bends and corners, does not catch on sheet metal screws and dmage the duct.
Ram Air is not the equal of units in the $20,000 to $100,00 price range. WOuld be follish to expect that. But it does a good job for the money.
As stated above Ram Air package is $1,000. That includes a lot of marketing materials. You will also need an air compressor and a Dust Downer an for most situations aditional air hose. Total investmetn will be around $2,000.
Some training materials come with the Ram Air. They could be a lot better. Additional training is being worked on now. It will be added to the package early next year and made available to current owners who ask for it.
Scott Warrington