Options for auditing data changes

I thought I will get some inputs on my following implementation. The requirement is to audit some data changes with in the system.( Oracle 10.2 on RHEL 4.7 )
The audit is required in a sense that, the before images of data and information of who changed the data is required. I have looked at options like Oracle Auditing,FGA and so. But this cannot give me audit for the data changes,when and who changed.

The first thing that comes into my mind are using triggers . Another option is using log miner. I have successfully tested it out with both of these approaches. The environment is like

1 ) For some critical tables for which audit is required triggers were written ( ours is an OLTP application )
2 ) For some non critical tables, log miner which was called by a stored procedure which runs at certain periods is used. 3 ) audit data is stored in a different schema , with same table names as in base schema.

I would like to know your thoughts on this.

Thank You,

Kind Regards,
Sreejith Nair

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