i'm not reading the replies, just posting my thoughts:
all the devices are AFM scalers, with the exception of the eman and it's added functionality via extra harnesses.
SAFC- cheap, effective @ what it does (scales AFM input to ECU), interface a touch cumbersome.
MAP ECU- overpriced. sure the speed/density conversion is nice, but why? the lex AFM flows more than enough for 95% of the users here. interface is OK, but @ the core it's still just an AFM scaler for $600....
eman- flexable. in base form it performs much like the old knob AFC. add the support tool (or E01) and the harnesses and you have a device that is as close to a standalone as possible. even w/o the harnesses, the ability to datalog and scale AFM via a 16x16 table is great.
funny the MAFT isn't mentioned here. it's a viable option and allows you to run blow through should you feel so inclined, along with it's AFM scaling abilities.