EXP/IMP vs. RMAN for backup
RMAN has many advantages that the logical backup with EXP/IMP cannot provide for you.
1. Ability to perform block-level incremental backups
2. Ability to backup your archived redo logs
3. Ability to backup your control files and SPFILE
4. Ability to report on those files that need a backup
5. Ability to recover to a point in time
Using EXP/IMP is not a valid backup and recovery solution, in my opinion. The EXP/IMP tools can augment your backup and recovery options, but I would never run a production database with just these tools as my backup and recovery strategy. You will not be able to recover to a point in time. You will have to manually backup your control files and your initialization file. If you have to restore, all objects restored from the dump file become "new" objects to the database, even if they have the same name.
I would strongly recommend that you implement RMAN as your backup and recovery strategy.
