The built from scratch is a more expensive way, if you want enough colors and wire gauges to be similar to an OEM installation. Bulk wire is expensive these days. I have never seen a Ron Francis kit, but I heard good things and bad things. I'd suggest getting a kit with a good fuse block with machine crimped connectors on it. The cheap kits sometimes use a bunch of aux fuse blocks stuck together as the main fuse block, and the crimping could be suspect.
As for the other end of the wires, most kits provide you with cheap insulated terminals that I would avoid. So factor in kit + good terminals + good shrink tubing (dual wall adhesive lined) + a few extras like junction points + harness wrap, or convoluted tubing or a bunch of tie wraps, grommets + some good tools.
I have no idea what Ron Francis supplies, try to get as much info as possible to be able to compare apples to apples.

Good luck,
Ran

"Hey mister, something's wrong with your car, it idles roughly" - number one comment I got in Israel when daily driving a 70 Barracuda with a lopey cam.

Currently working on - 1966 Dodge A100 van 318/auto
Finally - disc brakes on the front.
In the plans - rear disc brakes, B&M 250 blower