My rails (not ruby) experience: The deeper you go the more muddled you are; or better: At the end the ratio of rails and your own or third party code is 1:100

The only helpful thing in rails is ActiveRecord, you can also use separately. Distressful is that ruby and rails are by many people considered as the same thing. Those ROR versus PHP versus Java versus whatever-you-want are simply infantile. Please no flame and good luck :)