Confirmed by SE to not have a better chance at curing Doom.
"Hallowed Water (9/17)
Does this really heal doom at a higher rate?
Hallowed Water can be used as an item for further synthesis and can also be used to cure ailments like curse, however the latter effect is no different from Holy Water. If you happen to have some and you find yourself doomed with no Holy Water, it can serve as a substitute."
This item has a much higher success rate at removing Doom than Holy Water. More expensive, but they can turn an annoying Doom death into a win. When you also consider the wasted unsuccessful Holy waters, Hallowed waters might not be much more expensive when comparing how many waters it takes per successful removal.