The scepter is way lower damage than the Greatsword, I found. Greatsword has quite decent reliability, and its tools are very fluid and natural, from one to the next, and back again. Probably the best designed for a Mesmer. Scepter gives that up for "Here's a bunch of clones" which outside of shatter builds, seem weird to me. Almost excessive. Staff's a bit lower on the damage as well, but a decent rate of clone production.
Highest DPS would almost guaranteed be dual-swords.