Completing the canon of work by the Greatest Girl Group Ever. And though four discs is a ridiculous indulgence (we get both stereo and mono versions of two of the albums and a "vault gems" disc), there's no denying the essential genius of the 'Lettes, with or without Gladys Horton on board.
It's also true that, by the latter stages of their career, they had lost their teen brio and become a generic Motown bevy of ladies. But hell, it's the Marvelettes! Mwah!