What's the noun for preferable? Here's the word you're looking for.
preferment
(now historical) Prior claim (on payment, or on purchasing something); the first rights to obtain a particular payment or product. [from 15th c.]
(obsolete) The fact of being pushed or advanced to a more favourable situation; furtherance, promotion (of a candidate, action, undertaking etc.). [15th-17th c.]
“There is still no general consensus about the preferability of paper to plastic.”
“In some cases, environmental preferability could override cost concerns, giving the advantage to the greener product.”
“The traditional socialist emphasis on egalitarianism suggests the preferability of equal distribution of social dividend as a lump sum subsidy paid to each household.”