Can has a mix of both? Multiple systems, none particularly dominating the entire field of gameplay or design space? Although, uh, I do really love currency-based systems.

Alternately - and say what you will about the rest of Abyssea, love it or hate it - the system of "obtain eight/ten/whatever items, each with an individually high drop rate, from a set of NMs, and then exchange those items for equipment" does a pretty good job of balancing a sense of consistent reward against saturation of content.