Are devils worth 7 blood each?

[Boron]

Kel said:
Vampires are a great comparison. Same source, same type of product, same rate of production. Still have things to account for (like cursed items and research levels) but it's a lot closer than clams or bloodstones.

- Kel

Yep . Vampires + devils serve 2 different purposes imo :
Vampires are mainly defensive weapons , devils allaround weapons . So devils are a bit more useful and as others have said already the scout wastes no magetime while the Vampire lord needs to allysummon and each turn he does something else like forging / casting you lose a vampire .
So the RoI of the soul contract is really a lot better .

With forgeboni like dwarfenhammers , sites and the forge of ancients the soul contracts become really horrible .
You could really try to bring forge up as abysia . Your demonbreds could forge then earth bloodstones , fiever fetishes + your warlocks with only 1 +1blooditem or a lucky bloodrandom without that soul contracts .
So if you save your blood even if the forge gets dispelled after a few turns your gain is huge .