Mixed bag. It does work when you set it to the Yongnuo 568EX profile (Canon 600EX profile does not work). But it is inconsistent.
When you change flash power sometimes it doens't flash at all, then sometimes it does. It does pick up the change in power setting. It gets beter when you stick to a certain power setting, but not 100%. Pitty.
The Canon 600EX RT seems to function without problems.