Echoing what lvde said, there are many, many IronMail ripouts in IronPort's history ranging from small companies to some of the largest organizations in the world. But some of the customers who have replaced IronMail have policies not to publicly disclose their security vendors or vendor selection decisions. Since I don't know which customers have what policies I can't share these customer names but your local IronPort account team can get you a list of relevant customers that are OK with their names being shared. Some of these customers may also be willing to tell you their decision justification.

pat