I'm looking at running the video through a Y/C cable into an SD-connect, and then out to a Hard Drive. (picking up an SD-Connect will help me do this however :)
Anyway, the question is if Y/C will provide a better image than Firewire out (Camera is a DVX100) like Component will.
Are you looking at recording directly from the camera's S-Video outputs instead of from tape?
Once it's recorded as DV25 to tape then playing it back out through Y/C looses rather than gains anything. Same goes for component. You've already taken the hits from compression and color sampling and then you're adding in the losses of another D->A conversion and then another A->D step.
Coming straight from the camera though I really couldn't say. Probably best to ask over at dvxuser.com. One thing to watch for is the quality of the Y/C cable, we've found there's quite a difference between the losses in different cables.