I don't think "$bigcorp uses $technology" necessarily means said technology is serious and reliable. It can also mean they just have a big enough dedicated team

I don't think "$bigcorp uses $technology" necessarily means said technology is serious and reliable. It can also mean they just have a big enough dedicated team to adapt it well to their use case. Facebook uses btrfs in production and I'm sure it works great for them, but that doesn't mean btrfs is a good fs. And Jane Street has basically built their own stdlib for Ocaml, didn't they?