Does anyone have experiences with both ZGC and Shenandoah? It seems like they both have very similar goals (10 ms max pause) even though the implementation is quite different. So with both landing at about the same time, when would you prefer one or the other? Both seem like such a huge advance over G1 and so similar to each other that between them it doesn't look like it matters much.

Our team is going to be targeting ZGC for the main reason that it's included by default in JDK11. Yeah, builds of JDK11 with Shenandoah are available but it's more work.