Is there any level of service level support provided by Adobe CQ cloud?
Yes, Adobe CQ Cloud offering does come with a service level agreement from Adobe. See more information here: http://forums.adobe.com/docs/DOC-1703
As part of this offering, Adobe takes also care of patching your cloud-hosted CQ clusters when new versions of CQ are released.
On the other hand, when you start a CQ cluster using Cloud Manager, Adobe does not provide any kind of service level agreement for your CQ clusters.
You have the full control and responsibility for all CQ clusters you have started using Cloud Manager.