Processor upgrade for G4 PowerMac

[glock05]

Hey everyone,

Lately I've been looking into processor upgrades for a PowerMac G4 (AGP) that I picked up.
It currently has a 400Mhz processor with 1.5GB RAM (which I have upgraded already).
I've heard that the Sonnet Encore/ST G4 1.0 GHz upgrade is a good purchase.
Does anyone have any feedback or alternative suggestions in regard to this upgrade?