mechanicals work until they don't. Several people I know, shoot mechanicals because they "shoot the same as a field point(LIE). They don't want to put in the time to tune a cut on contact. I've got my bow driving tacks with G5 montecs. But I'm about to order some new shafts and heads and push for 19-25% FOC and just tune, tune, tune until I get them flying straight.
Another thing, shot distance. At a foam target I'm 100% confident in shooting 30+ yards. At an animal 30 yards away, they have more than enough time to react to the shot. I don't plan on shooting at an animal more than 30 yards away. Really, beyond about 25 yards no matter how perfect my form and patience is, the outcome is out of my hands and mostly based on that animal reacts to the sound of my bow firing.