Strata VideoShop is a good choice. It was commercial software, released as freeware by the vendor. It has most of the editing capabilities of something like Premiere.

Supposedly FusionRecorder can capture better framerates than any other software on the AV Quadras by not using a QuickTime VDIG. I guess it talks to the hardware directly...? I always used VideoShop and got results as good as expected.

The comment about not capturing much video on a 660AV is about how the AV Macs lack hardware video compression. So, that means you have to capture at low frame sizes, low frame rates, or both, limited by how fast the CPU can compress video.