I've only tried this on my trunk because I haven't had much time but I promise I'll do a full evaluation! But as far as swirls are concerned, it doesn't really do much to hide swirls. Maybe some, but minimal.
Softball nut - that sounds like something you should try on a small area. I applied the WF pre-cleaner and sealant, on a wax free surface and the results were great. I had no problem at all with the pre-cleaner going on or off like others have stated.
I love WG more than Zaino, but WG has as much swirl removal hiding ability as Zaino Z5 does. How much does Zaino have you ask; non in my humble opinion.
I belive if you ahve swirls and scrathces you need removed use products designed to do just that then apply WG or Zaino.
I used the precleaner and sealant by hand on my new WRX that the dealer had completely swirled on the sides, and I think it's at least 80% better than when I started. We'll see how long it lasts, but so far, so good.
As it says on the website, the pre-cleaner is a chemical, not abrasive, cleaner. It "fills in the swirls" and "rounds the edges" so the swirls "seem to disappear." I tried it on my girlfriend's car. She's used the snowbrush on it regularly and has been caught once using the scaper! ("I was careful. I couldn't find the brush and I was in a hurry.") I didn't seem to notice much difference, and I tried different techniques/amounts. I think it may make the swirls seem less noticeable if you don't see a direct light source reflecting off the paint. It did seem to lessen the noticeability of some scuffs though.
I'm definately going to have to do some more work on it than just the hot wax at the car wash!