yarn has resolved most of the issues already :)
We’ve seen more issues with Yarn in CI & prod than with npm 5.x
Both are great projects but npm is significantly more mature.
Still have to do the install on a deploy server.
We do use private scoped packages a lot so that might have some bearing on it.
Would be interested in specifics of your reliability and failure problems too.
Yarn claims to be deterministic but I still need to `rm -rf node_modules` regularly when I run into weird build errors. It's quite strange.
I had mistakenly setup our CI to do that at one point and it caused a lot of hard to debug problems.