Postfix has been around for decades and respects the Unix philosophy of doing one thing and doing it well. It's perhaps the most widely deployed MTA, and as suc

Postfix has been around for decades and respects the Unix philosophy of doing one thing and doing it well. It's perhaps the most widely deployed MTA, and as such it has been thoroughly field tested. Also, people in the FOSS community tend to be wary of "open source" projects primarily developed by a commercial company under dual licensing.