Hi Sergio and Daniel,
I am not personally experienced with SCCM, but I am aware of some differences between the two products based upon conversations with people who are familiar with both products. Also, please keep in mind that both products are enterprise-class and continually being improved, so some of the information here may change or be possible via custom workarounds.
Most notably, SCCM, being a Microsoft product, is focused mainly on Windows, while CA Client Automation is multi-platform (in terms of agents, patch content, as well as some infrastructure). My understanding is that SCCM requires/relies on Active Directory, while Client Automation can leverage AD without being dependent on it. CA Client Automation provides flexible architecture and configuration options, while SCCM has been described to me as “server-heavy” and complex. CA Client Automation provides multiple methods of software discovery, which are also configurable and customizable, which is important to people who are running IT Asset Management programs and need to match software licenses to installations. The Remote Control features of CA Client Automation provide robust auditing and security features which don’t seem to be similar in SCCM. I have also heard that the software delivery capability in Client Automation provides simpler yet more flexible grouping and scheduling options. CA Client Automation recently added a Neighbor-aware Software Distribution feature which allows agents to get payload from neighboring agents, which allows for faster mass deployments of software packages. Not sure if SCCM has anything similar. CA Client Automation also allows for device management over the Internet with the Extended Network Connectivity (ENC) feature. Again, not sure if SCCM has this.
I hope this helps.