[niterydr]

s-afc, 8 adjustment points (i think it is) hi and low throttle settings, very easy to use, very easy to tune with, very easy to 'mess your car up' thinking you are 'tuning' it.
hks afr, 12 adjustment points, no 'hi/low' variences, has an idle mode with 6 points If I recall that can be used to combat the effects of a vented bov, but doesn't work as often.
s-afcii- 12 points, has hi and low throttle settings x2 maps (very nice)..my only beef is navigation is slower than the s-afc, and the screens switch to damm fast!
other options:
greddy emanage: as a base unit, very lame, 5 adjustment points +/- 20% airflow signal, but with the add-ons can become a very competent piggy system 16x16 fuel map, 16x16 ignition map, map sensor compatible to continue controlling fuel after mas overrun, etc..etc..
can't think of who else makes piggy's.
Then there are vpc's, arc's, and the host of standalones out there, aem, haltech, autodyne, grr can't think of there other ones, I think there are over 12 now.