I did it at Air Combat's Fullerton operation back in July of "98, and it was an absolute hoot (got to fly against an aspiring instructor pilot, too). They'll give you an excellent condensed briefing on ACM (I suggest you let them know you already know the basics, they'll accellerate it a little). Then you fly out to the practice area (in SoCal it's over the Catalina channel, about 15 minutes from the airport). The flight will let you get use to the controls and maybe do a little light acro once you get to the practice area.
My instructor pilot, a former Luftwaffe F4 recon pilot callsign Baron, was a GREAT coach, and we did all 6 fights in the vertical. He REALLY knew his stuff (including anticipating the E-state of the opposing plane in a way that seemed supernatural)and was a great coach (he never touched the controls). He also seemed pleased (if a bit nonplussed) when I yelled "Horrido" over the radio, hehe.
One hint: being real fighter jocks who are used to dealing with ejection seats etc. the ACUSA pilots seem to have a tendency to look back over their shoulders, even when going vertical. I guess the ejection seats prevent you from just tilting your head straight back, like I'm used to as an acro pilot. I think tilting your head straight back and looking up over the tail of the plane (like AH hi-6 view) gives you a better field of view when going vertical after the merge.
All in all it was one of the great experiences of my life, and I look at the tape of it whenever I need a pick-me-up. If Baron or Loopy (he was the aspiring instructor who was my opponent- former A10 driver)are there, say "hi" for me (and remind Loopy about the former tanker who ruined his whole day back in July of '98).
ENJOY!
