California community college to CSU is better in terms of articulating the required transfer courses via assist.org.
CSU to CSU transfers do not have specific articulation agreements so the student needs to use the assist.org and the SLO website requirements and try to match them to the current CSU course’s.
CCC to SLO transfer is much more straightforward and if the student attends a CCC in the local SLO admission area, they get transfer priority. Not a guarantee but it helps.