"It's been a long time since I wrote any code"*, but today while writing something I have finally solved this religious debate once and for all.
The answer is spaces.
And the reason is simple - with 6 indents (4 spaces each obvs) you can play the intro to Led Zeppelin's Rock and Roll (from Led Zeppelin IV).
Case. Closed.
* - "Been a long, lonely, lonely, lonely, lonely, lonely time".
<--- drops mic