Lots will be said about these two RAW-workflow tools (and already has been said), but with both appli­ca­tions hav­ing tri­al ver­sions avail­able, you real­ly need to try them for your­self. I found the Ars Tech­ni­ca review espe­cial­ly inter­est­ing as it pro­vides sam­ple images from Light­room, Aper­ture, Bib­ble and Cap­ture­One so you can see the dif­fer­ences in res­o­lu­tion, col­or, noise, etc.

Light­room: “Inno­vates in its own way by pro­vid­ing a moth­er lode of intu­itive adjust­ments, many ways to nav­i­gate and tag a huge library of images and it does it with speed to spare.” (via ArsTech­ni­ca Review)

Light­room: “Adobe’s next gen­er­a­tion pho­to soft­ware is a full-featured, all-in-one imag­ing solu­tion for seri­ous shoot­ers.” (via PopPhoto.com)

Aper­ture: “(Aper­ture 1.5.2) brings the pro­gram even clos­er to ful­fill­ing its promise as the start-to-finish, import-to-output hub of pro­fes­sion­al and advanced pho­to­graph­ic work­flow. Seri­ous dig­i­tal pho­tog­ra­phers should give it a look.” (via Mac­World Review)

Aper­ture: “The program’s non-modal inter­face; true real-time, non-destructive raw work­flow; and excel­lent orga­ni­za­tion­al tools put it head and shoul­ders above the com­pe­ti­tion in terms of easy, effi­cient work­flow man­age­ment and post-production.” (via Cre­ative­Pro)

Also, enjoy these resources for both apps:

Light­room Learn­ing Cen­ter (NAPP)

Aper­ture Resource Cen­ter