[savanaly]

Major advantage: fewer characters to type and parse (parse with your eyes, that is).

Major disadvantage: in the short term it might be difficult to parse.

Possible additional major disadvantage: programmers may never adapt and find it difficult to parse for ever more.

[atinoda-kestrel]

Yeah, I'm not sold on "fewer characters" as a win. 'cause then we can have the code golf arguments that inevitably get into the nutty realm.

For visual parsing, consistency matters. In an object literal dec I expect:

  name : value

That's easy to parse visually. Not good is when suddenly we get:

  nameandvalue(){

in the space that our brain expects the former.