Thanks both of you for your insights into this question. I am not in the enviable position of being able to buy a machine with a servo, so clutch motor it is, until money allows for an upgrade.
The two machines I mentioned are of adequate quality to sew 1000d to web, and do not see an immediate need for a walking foot machine, though it sure would be cool to eventually add to the quiver, and to help binding with grosgrain/ repairing marine canvas.
For now, I'll be making backpacks. Thanks again!