I like the following sentence a lot: "It depends on your project" :)
If you have a very small module, you could go for CoffeeScript. It is ultimatively an uglified version of JavaScript, leaving out a lot of semantic overhead resulting in smaller code which can be easier to read. But only when the code is small either way. I would not recommend it at all for bigger projects.
Dart actually has yet to see some more love. I haven't played around with it a whole lot, but I'd say it is very comparable to TypeScript; but it's Google instead of Microsoft, so maybe the decision between those two might be more of a political decision... One argument against Dart might be that it does not have the same traction and a smaller community. But it depends on your project if something like that really matters...
Then there is the odd one out: Babel. Babel is not a language. It is a mere tool. Babel is nice if you want to transpile stuff, but when you have official tools (like the TypeScript transpiler by Microsoft), you just do not need it. Imho, Babel shines when you want to use ES6 / ES7 features, but have to support old clients.
You also listed Clojure, which I have absolutely no experience with, so I will leave it out for now.
To put it in a nutshell, since you want to move away from JavaScript, you might want to consider using either TypeScript (going with the hype; TypeScript is still based on ES) or Dart (very nice language by one of the companies driving the Internet).
Personally, I would stick with vanilla JS as ES6 adds a whole lot of very nice features. If you really have to, you can use Babel to transpile it to ES5 for older browsers.
Here is an interesting read for you!
PS.: I get the feeling that you seem to have a missunderstanding about ES and JS. ES is not a language. It is just a standard! JS and many other languages build on that standard. The so-called JS2015 builds on the ES6 standard. TypeScript also builds on ES. Afaik Dart does not build on ES, but was standardized by the Ecma Consortium (correct me if I am wrong).