It didn't work for me. Tried opening a page in Safari on iPhone, and creating a message.
No response from iMac with 10.11. Walked into the other room and set the phone next to Macbook Air running 10.10.x and it responded as expected.
It is working after opening iCloud settings. Beachball came up for a bit, and the handoff icon popped up in the dock when it went away.