Quite\rather

[abra]

(We use quite\rather with the base form of an adjective, rather with the comparative and quite with the superlative.)
Thanks for the tip, Tdol

[Wuisi]

Maybe 'best' is non-gradable and we are supposed not to use 'rather' with non-gradable adjectives; we can say 'rather good' or 'quite good' but not 'rather perfect' but 'quite perfect' (quite here means 'completely, absolutely')