These are basically two different signalling protocols. SCCP is the native signalling used with Callmanager SCCP is also called Skinny, SIP is an open standard.

Most Callmanager deployments in my experience are still using SCCP for signalling.

The 7960 can support either SCCP or SIP.

I would recommend using SCCP unless there is a specific reason to use SIP.

Hope this helps.