I would love to see it used with real-world examples. There are two main situations IMO where this would be useful:
- For developers creating websites. The cost of set-up would be high because you'd need concatenation+minification+etc in place, so I'd love seeing some examples to see whether or not is worth it. From what I know, this could be similar to tree-shaking, so there could be huge gains here.
- For library creators. However the top-most variables would have to be preserved, since other developers need to use them (which seems possible[1]), so I'll be trying it out.
I am also wondering about the performance boost for JS (besides file size) and whether this would be useful for something like Node.js or not (free performance). If anyone has more information please share it.
I don't have a direct comparison to Uglify, but as of last fall advanced optimizations does save us about 2.5 MB over simple optimizations.
We're also using Tsickle (https://github.com/angular/tsickle) and Clutz (https://github.com/angular/clutz) to be able to use TypeScript with our Closure Compiler compatible codebase. Closure Code can be depended upon in TypeScript code and vice versa. It's been awesome to use the type system of TypeScript in combination with the minification power of the Closure Compiler. The build process is definitely a bit crazy at the moment, though.
Disclaimer: I work at Lucid Software.