Block scoping (using const/let instead of var which is scoped to the function) alone is really nice, but I also make heavy use of destructuring, arrow functions, template literals, export/import syntax and promises. Es6 makes javascript more pleasant to code with, and can greatly improve readability.

es6 has become pretty well supported by modern browsers, so maybe after a year or so, we'll just be calling it "javascript" and running it without babel. I expect everyone to continue to transpile, though, to get newer features as they come, as the plan for ES is to release new language updates on a yearly basis.

It adds some extra nice language features to JS. It really is a good productivity improvement, especially with JSX which enables HTML literals: pretty much essential when working with a complex React front-end in my opinion.

My team has been using it for most of this year now and we've had no problems so far.