Garuda's Scream @ the same stats (STR/VIT below cap) as Ifrit's Battle Axe will pretty much do the same damage.
The added accuracy + capping the stats is a huge gain, trumped only by the Relic. So yeah Garuda!!!
You may not be too far off there. The difference in DPS is only 0.77 (~2% difference in damage)I use Immortal Flames Sergeant Axe if I want max HP (with Sanction it's superior, because of it's immense AtkPwr bonus)
The Flame Axe with Sanction and the +45 ATK (~4.5% extra damage)
So ~2% higher.
Capping the stats will still bring Garuda higher, + 25 Acc. But that is the reason people us it.
** The stat numbers came from testing I've been doing on the % gain per stat and should not be taken as 100% accurate