Verify that you can restore the server archived. This will satisfy the most rigourous legal and forensics requirements IF the chain of control is maintained. If the tapes are dumped and stored under lose control, forget it. Comma-delimited data can be easily moved to databases such as SQL for centralized processing. More and more commercial products use this approach.
Text format has the advantage of simplicity.
It can also be a starting point for processing using mature unix-oriented data manipulation utilities. A mixed situation is the use of tools like dumpel.exe which can dump event log file data. It dumps the text data and translates the much of the hex data to readable text formats. My final point is that this is not an either-or situation. Save your checkpoint full backups and use extracted text or comma-delimited copies for programmatic processing.