I used log4plsql years ago and start dto do it again. It helps to create a standard for logging in your system while you do not have to invent the wheel of proper logging again (and aggain) :) Runs stable and has all the features i need.
This project has helped us in getting a summarized view of the database activity in test databases. We are able to find issues faster and improve system in production using logs. I recommend this project to anyone using Oracle database and PL/SQL code for DML operations. It is extremely helpful in getting a summary of errors happening in the system using a single table in database itself.