Well, the sinodefence-site mentions the missile: http://www.sinodefence.com/navy/navalmissile/3m54.asp
The Sizzler is smaller in size and lighter. I think the main difference is that the sunburn travels at supersonic speeds all the time, therefore requiering a big load of fuel, wich in turn makes the missile big and heavy. The Sizzler cruises at subsonic speeds and goes supersonic in terminal phase. But there are different versions of the "Club" some are "conventional" subsonic CMs over the entire flight.
The range is rather bigger than the sunburn's.
And I think the Sizzlers also have the capability of interoperability. Meaning they can exchange info. One "lead" missiles flies at high altitude searching for targets with it's radar, while the other missiles of a barrage stay low and recieve info from the lead-missile.