I don't have any large rules that act on 50+ z-wave devices, but I have noticed that there is a longer lag in JS vs. ZIP. I have a z-wave button that triggers a rule which turns out lights on 2 z-wave switches. Both my wife and I have noticed that there is a longer lag between button-push and lights-off when we are running on the JS stack.
I have documented the issue in detail on this thread: Is anyone else experiencing a ~500MS delay when running ZwaveJS? - 
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I have my rule set to log the trigger event. By looking at the entries in the system log and the z-wave logs, I can see that is a ~500MS delay between when the button-push is logged in the z-wave logs and when the trigger event for the rule is logged.
Marc
