For me, brass annealing is about extending brass life, not accuracy (although that can be a possible byproduct depending on more than a few factors of cartridge components and cartridge build).
I consider flame annealing brass a craft, whereas AMP is, well, as perfect as one can get.
The prime difference 'tween the two is accuracy and cost.
With essentially the three methods of brass annealing - manual electric drill w/flame, automated flame annealing machine, and AMP - I first tried the manual and quickly realized it was too "crafty" with less consistency from brass to brass, and started using an Annealeez machine. The machine is, for me, super easy to set up for annealing any rifle brass that in turn extends my .223/5.56, .243. 6.5, .308, .45-70 brass life for what seems like forever. YMMV.
I consider flame annealing brass a craft, whereas AMP is, well, as perfect as one can get.
The prime difference 'tween the two is accuracy and cost.
With essentially the three methods of brass annealing - manual electric drill w/flame, automated flame annealing machine, and AMP - I first tried the manual and quickly realized it was too "crafty" with less consistency from brass to brass, and started using an Annealeez machine. The machine is, for me, super easy to set up for annealing any rifle brass that in turn extends my .223/5.56, .243. 6.5, .308, .45-70 brass life for what seems like forever. YMMV.