I implemented Sprint Zero with my team last January with an 8 days Sprint and it worked really well for my team. The team was able to produce a working software in a very short period of time. The management was impressed.

The people I have in my team when I did the Sprint Zero has no previous experience with Scrum. So it was an immersion experience for them.

We actually called it Sprint Zero back then. So this article was like a validation that what we did before is actually working.