We are actually doing an internal Audit either next week or the following. The biggest advantage about the internal audit is that potential issues can be addressed early before the outside auditor arrives. A corrective action can be initiated to address these problems early, thus when the external auditor arrives they are aware that actions are taken to address underlying issues that were discovered within the internal audit. I would assume that the biggest con would be bias towards inspection because unlike an external auditor and internal one is more familiar with most areas of inspection and company procedures which could indirectly effect the results of the audit.