You would be mad not to get a Ramsey -07. They are very very common, and cheap as hell as they were used in A4000. Whereas the DMAC -04 is very rare and VERY VERY expensive because it was A3000+ and upgrades only there are considerably less of them than there are A3000's. WTF did you find yours?
Benefits are stability with accelerators. If you have no turbocard you probably wont see any difference.