As dick scherrer says, it depends.
Many people feel COND is very confusing. I'm among them, and I've been writing JCL for more than 40 years. On the other hand, the // IF statement is quite verbose, and it can be confusing for that reason.
For example -
//A EXEC PGM=WEEKDAY
// IF A.RC=0 THEN
//B EXEC PGM=WTO,PARM='IT''S SUNDAY'
// ELSE
// IF A.RC=1 THEN
//C EXEC PGM=WTO,PARM='IT''S MONDAY'
// ELSE
// IF A.RC=2 THEN
//D EXEC PGM=WTO,PARM='IT''S TUESDAY'
// ELSE
// IF A.RC=3 THEN
//E EXEC PGM=WTO,PARM='IT''S WEDNESDAY'
// ELSE
// IF A.RC=4 THEN
//F EXEC PGM=WTO,PARM='IT''S THURSDAY'
// ELSE
// IF A.RC=5 THEN
//G EXEC PGM=WTO,PARM='IT''S FRIDAY'
// ELSE
// IF A.RC=6 THEN
//H EXEC PGM=WTO,PARM='IT''S SATURDAY'
// ELSE
//I EXEC PGM=WTO,PARM='I DON''T KNOW WHAT THE WEEK DAY IS!'
// ENDIF
// ENDIF
// ENDIF
// ENDIF
// ENDIF
// ENDIF
// ENDIF
The WEEKDAY program returns the day of the week when it's run as a return code from 0 to 6, and WTO does what it appears to do.
Compare the previous JCL with -
//A EXEC PGM=WEEKDAY
//B EXEC PGM=WTO,COND=(0,NE,A),PARM='IT''S SUNDAY'
//C EXEC PGM=WTO,COND=(1,NE,A),PARM='IT''S MONDAY'
//D EXEC PGM=WTO,COND=(2,NE,A),PARM='IT''S TUESDAY'
//E EXEC PGM=WTO,COND=(3,NE,A),PARM='IT''S WEDNESDAY'
//F EXEC PGM=WTO,COND=(4,NE,A),PARM='IT''S THURSDAY'
//G EXEC PGM=WTO,COND=(5,NE,A),PARM='IT''S FRIDAY'
//H EXEC PGM=WTO,COND=(6,NE,A),PARM='IT''S SATURDAY'