Jaguar + dual G4 upgrade

[Fugazi]

I currently have a G4 450 AGP tower w/ 1 gig RAM.

Assuming:

• Jaguar performace improvement on dual-processors is as great as we're led to believe AND
  Many of my main apps are (or will be) programmed to take full advantage of DP

Is it worth considering the Sonnet G4 Duet upgrade (G4 500 x 2) for $600? Or would I see better overall improvement with a G4 800Mhz single-processor upgrade @ $500?

If the Duet drops by another $100 I'm going to seriously think about it.

Bill