i got yelled at alot by a friend over the knockback, and so ive since strictly used ifrit, because i admit i am lazy as hell but also i feel like radiant shield is a great buff in general, he seems to stun a little more smartly than garuda does her knockback on auto. However the cost of this is loss of contagion, which auto garuda will never use properly ever anyway. The best way to play summoner is manual, but i just cant resist the aoe and burst for every day stuff like dungeons.