I have been testing SCCM and application deployment for past few months, not had any major issues.
Finally made the plunge to push out an application in production after testing it without any issues.
Firstly it has taken ages to deploy, even though I said deploy right away.
Secondly most of the deployment failed for unknown reason.
About 5 were successful, 5 already had the software installed and about 20 have failed to install for unknown reason.