[ameliaquining]

It's better in some ways (order-of-magnitude reductions in pause times were cited) but worse in other ways (higher peak memory usage). That the higher peak memory usage was catastrophic for some users only became apparent through post-release feedback.

[petre]

They should have shipped it as an addon GC, not enabled by default. One could have turned it on with a command line switch or an env var, just like the Ruby JIT.