Knowing nothing about electronics or wiring needs when I got to the place in my building process where I needed to decide what to do, I simply ordered Van's wiring harness. I knew it was basic, but I was not planning to do anything special. I bought the harness that provided for the battery on the firewall.
Fast forward to the time I REALLY needed to start wiring. By then, my engine choices had expanded and the consensus among -8 drivers was by then that the battery should be mounted in BACK, regardless what engine you choose. So, rather than cobble together the large-gauge wires that I would need to make the changes, I just ordered the other wiring kit (that was designed for the battery in the back).
Along with the changes in engine choices, the glass panel revolution was building up steam, and I abandoned my steam gauges for a pair of Dynon units. Other than having a bunch of pre-made wires left over (along with extra switches and terminals which later came in handy), it only wasted a little money and gave me the assurance that the important wires were well-made and of the right size and length. For ME, that was important.
Stein's panel wiring didn't put any demands on the stock Van's wiring harness that I couldn't accomodate. I'm sure Stein makes a fantastic wiring system, and agree with the others that if you're planning a unique wiring plan, you can't go wrong with anything he does.
And, yes, he paid me to say that.