You see, at the moment we have approx 150-200 domains and 700 email accounts on our system, and an average outgoing mail queue at the moment of 3200 at any one time at the moment (because a few clients had catch-all accounts with autoesponders on, hence truck loads of autoresponder messages being sent out to non-existant spam email addresses in the last day or so), although this seems to be running perfectly fine with these amounts of accounts etc, it would be nice to know if anyone is running higher amounts than this so it kind of gives me an idea of how far it can go before screaming for help

Since we also offer backup mail services with this server, the outgoing message queue could increase significantly in a short space of time, so having an idea of whats its capable of will help towards how many accounts and services we can comfortable provide with it?