[dba-SQLServer]Audit log

Hello,

for a customer I need to implement an audit log. There are a couple of
commercial tools available, that take the task of creating the log table and
triggers required for that (e.g. Krell Software's OmniAudit or Red Matrix'
SQL Audit).

Does anyone have experience using tools like that and might want to share
his/her experience?

Are those tools worth their money or might it be easier/cheaper/more
flexible to implement that myself?

TIA,

Michael