As for performance, Yarn is about 3-5x faster installing all of the dependencies and devDependencies of react-native. The benchmarks are here: https://yarnpkg.com/en/compare. It's much faster in most scenarios, especially the ones that used to take minutes.

Only if those dependencies are in the cache, otherwise it takes the same time.

The benchmarks test both the hot cache and cold cache scenarios for npm and Yarn. Except in the scenario when node_modules is already populated and there is no yarn.lock file, which is uncommon if you're using Yarn, Yarn is faster than npm in all of the benchmarked scenarios where there is a cold cache.

  > unless you've actually shipped a product using this tool 

Given that wycats _worked on_ this tool, I would assume it's his experience helping build it that's the basis of the claim.

(I don't work at Tilde so I can't tell you if it's been shipping with yarn, but it would shock me if it wasn't.)

We're not using Yarn at Tilde yet, but I've been using it on Yarn itself and when working on Ember packages, and it's worked well. As far as performance, we have good benchmarks tracking yarn's performance in a whole bunch of different scenarios (https://yarnpkg.com/en/compare)

Ok, didn't realize he worked on it. Bundler is great so that gives me some hope for Yarn. But in general I think its more stable in the long-term for projects to use open standards instead of vendor solutions for browser package management.

I can understand this sentiment in general, but don't think it applies here. npm is also a private company, and this does work with their registry. There currently isn't a vendor-neutral standard to follow.