I found that the washer attachments to the air compressor were suitable for washing cars and light cleanup, but the one I used, even with a big compressor, really was not up to the task of stripping paint or cleaning decks/siding, etc.
I decided to bite the bullet and buy a gas-powered, 1800 psi from Sears. This is not a plug for them, but their repair centers often have good deals on refurbished units. Thatís what I bought, and the unit was much better than the bottom-of-the-line models, with separate oil supply for the pump unit (increases its life). At $250, it was over $125 less than new, and even less than the bottom-of-the-line gas-powered units. It has not given me any trouble in a year of heavy use.