Features provided by the RMAN, but not from User Managed Backup

1. RMAN stored frequency used scripts
2. Change tracking background process (CTRW) is introduced for incremental backup
3. RMAN can control the backup pieces size
4. RMAN can recover an indiviual data block or set of data block of a data file
5. RMAN can integrate with the Oracle Scheduler
6. RMAN can detect block corruption. there hase 2 dynamic views are useful for this, V$BACKUP_CORRUPTION, V$COPY_CORRUPTION
7. RMAN has performance improvement
8. RMAN has media management API
9. RMAN help to keep track of all database files and backups.