In terms of cons, (off the top of my inexperienced head)
If you use files, you have twice as many things to manage. Where you had database-handling code, you need to add file-handling code. If you delete a records, you also have to delete a file. You have to backup both the database and the files. If you had load sharing, you have to share the database and the files. In other words, twice as many things can go wrong. Also, a database adds (limited) searchability.
The cons for using the database might include increased database workload, and data size limitations.