1. That is debatable, there is a lot of inactive time, 10 mins to make the brine then it's just sitting in brine, 10 minutes to get it in the sous vide bath, you don't touch it then. 10 minutes to make the rub, 10 mins to take it out of the sous vide and apply the marinade / rub, then slice. This spans the course of days, but is very simple without much clean up.
2. I'd say the rub and all of the marinade stuff is about $20. So there is your incremental cost, although some use a rub for their BBQ brisket too.
3. I'd be willing to bet that 99 out of 100 people wouldn't be able to tell a true bark from this bark in a blind taste test. It really replicates it that well.
I'll be the first to say that this isn't BBQ, it's not even close, but it's just another way to skin a cat. And the deliverable is top notch.
One day I'm going to learn to smoke meet, I just have never gotten into that hobby. I want to build a pretty serious smoker in my yard, there will be a time.