Depends if you care more about performance or about debugging and troubleshooting on Production. If in a stable Production environment, use "LOG(4 00 *NOLIST) LOGCLPGM(*NO)". This means to only generate a joblog if the job ends abnormally. Each CL command that is executed is not logged to the joblog.

If in a much more volatile environment with constant changes and Production issues, "LOG(4 00 *SECLVL) LOGCLPGM(*YES)" will give your operators and developers much more to work with. All jobs will generate joblogs regardless of whether they end abnormally. All CL program commands are logged into the joblogs which will be helpful for troubleshooting issues.