TL;DR this post tries to explain why a compact solution based on a NON visually configurable predefined amount of spaces wins through facts and not personal style choices. If you'd like to argue please have the decency to read this post top to bottom before that. Thank you!

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I've got 99 problems and "spaces VS tabs" actually is one of them!
I find it embarrassing for the entirety of the programming, developers, and designers worldwide industry and community to still have these kind of debates in year 2015!
We laugh about medieval people thoughts, modern bigotry, or how stupid is from time to time the rest of the world around us ... and yet we cannot stop whining about spaces or tabs.
Moreover, the untold story about this debate is that everyone is simply being selfish and every rationale behind is made of opinionated and volatile fluff that does not match current real-world scenarios (yeah, maybe me too, but before that, please keep reading 'till the end, thanks!).

Defining a Standard

There are few standards and protocols universally implemented in the programming world and JSON, as well as XML, are just a few and rare examples.
There is no "my XML is better than yours" or "my JSON looks nicer" discussion there, as soon as you write something not conforming with the standard you are causing troubles either to your own code and yourself or to whoever needs to consume your code!
There's not "but ..." or "because my style ..." here, there is only one way everyone understands which is the only compatible way and the best way to move forward.
Unfortunately, in the history of Computer Science (funny it's called Science in this case) there's still no agreement on the "spaces VS tabs" matter.

Fact 1: Nobody wants horizontal scroll

Not only books are read vertically since ever, "technological mouses" are not even created to simplify such task and on top of that: if you don't set yourself a limit to the amount of columns your code should actually warn you, usually 80 up to 120 chars, it doesn't actually matter what choice you made to your indentation because "'yo column is so wide I though you were a code cruncher instead of a human being".
We don't like to scroll horizontally and we would like to be able to put 2 or more different files beside each other to compare diffs and lines in a single screen ... right?
In other words, it's OK to have 80 to 120 chars column width limit because we all agree it's needed!
Then we have either developers that connect via SSH, those that use daily vi or vim, and people on Smart Phones that maybe are surfing online, studying some piece of code where they also have to scroll every single pre tag because by default each browser uses 4 or 8 spaces to represent a tab ... you say no?
This is something standard to show to you, it doesn't have any special parsing behind, it's just plain code.

// 2 spaces indentation random code
class View {
  constructor(options) {
    this.model = options.model;
    this.template = options.template;
  }

  render() {
    return _.template(
      this.template, this.model.toObject()
    );
  }
}

// its tabs based equivalent
class View {
        constructor(options) {
                this.model = options.model;
                this.template = options.template;
        }

        render() {
                return _.template(
                        this.template, this.model.toObject()
                );
        }
}

Before asking ourselves which piece of code looks universally better, I just would like to show you a couple of cases different from your editor of choice scenario:

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