In general, a mirrored RAID is best for minimizing data loss and downtime due to drive failure, while separate volumes and periodic backups is best for recovering from accidental file deletion or malware. (I.e., if a RAID gets told to write bad data, it’ll overwrite the good data on both drives at once.)
If you want the best of both worlds with just two drives, try zfs—you can mirror the drives to protect against drive failure, and make snapshots to protect against accidental data loss. (This still won’t protect against everything—for that you should have some kind of off-site backup as well.)