Carrier class email security recommendation

I am in the process of sourcing for a carrier class email security solution that will replace our current edge spam gateways based on open source solutions. Some solutions that am currently considering are Ironport, Fortinet Fortimail, MailFoundry and Barracuda. I'd therefore wish to know, based on your experiences, what works for you satisfactorily. Areas that are key for me are centralized management and reporting, carrier class performance, per mailbox policy and quarantine, and favourable licensing for an MSSP. I know Ironport is rated highly in this space but I find its per user licensing is not favourable for a MSSP. Regards, Alex.