FTG V2 is faster than Ameno.
How is flying raijin more faster then ameno?
They are both the same in speed, but ftg has greater range while ameno needs no prep or seals.
Same,both are instant.
This. Though Amenotejikara doesn't require a setup, when launched, both arrive instantaneously. On the other hand, Hiraishin is unlimited so long as the seal is set, since Amenotejikara is a dojutsu, it only works on a target they can see.
They are both instant. You don't get faster than instant.
Reaction time after said instantaneous teleportaion, however is another story.
Hirashin has the greater distance
amenotejikara is more efficient in execution as it doesn't require a seal to use
Hirashin doesn't have a cool down time and has a limit of 5 seals.
It really just comes down to the skill of the user. Neither is faster than the other. Just the users reaction time once the jutsu finishes.
amenotejikara is faster since you don't have to use tags like a noob

4th hokage couldn't use it to save Naruto. He said he is low on chakra during that moment.