I think that neither Millicent nor DSR dominates the other. While Millicent's transaction costs include a strong hash, and that it much cheaper than a public key signature verification, DSR's simple 32 bit add is far simpler still. Scrip must be stored and records kept of spent scrip. DSR must pervade the communications fabric. They would compete for buying a web page that cost a few cents.
Neither is perfectly anonymous; both can support anonymity.
I quote:
We take a decentralized approach in which local site managers think globally but act locally, making local resource allocation choices to converge on desirable global outcomes based on information disseminated through the service overlay.From our Hayekian perspective, we doubt that this is possible, but it will be interesting to see what they achieve. We agree that sociological metaphors are useful. We depend, almost ideologically, on market mechanisms for allocating the crude resources. Between buyers of the high level globally optimized result, Opus discriminates according to what they will pay.
Global optimization is hard; it is best not to make it a monopoly. We wish to enable market mechanisms to help solve the problems that the Opus paper outlines well.