There used to be very little or no delay at all. I could use my hue dimmer to control my LightwaveRF dimmer through the integration. It now doesn’t work as well.
I found this description on another thread from a while back:
Do we need to go back to refreshing the lights every x seconds to get timely status?
As a workaround, I have added a CoRE rule to wakeup every minute to refresh the lights, but this isn’t a tidy solution and may also be anti-social.