I did the same thing last fall, and used a swirl mark remover. Like you I was amazed at how great it came out. The swirl marks stayed away for a few months worth of washing, but they and a light haze were back by now. Sunday I claybarred, polished and waxed. Looks really good, but not as good as when I used the swirl remover.
So to answer your question I'd say the swirls will only stay away for a couple months or so :-(
One hint I read/learned is to only wash and chamois the car in certain directions. This has significantly reducced teh swirls in my black paint. I only wash/chamois in solid strokes along the length of the car when doing teh doors and quarter panels. I do the hood and facia in solid strokes along the length of the car also. Do not stroke the doors up and down, or stroke the hood across the car. This way the fine scratches follow the body lines and are not as noticeable.
