I was very curious when I saw you were doign a Mailserver roundup, however quite suprised at the results.
I thought it very odd (and without much backing) that postfix got such a low rating compared to the others.
I use postfix on all my systems (going from home computers only for logs etc, to 50/100 user systems where each person has mail account, to large enterprise systems, where large batches of 500,000+ emails sent out at a time). I have no problem with you giving it a 5 or otherwise, but I would be curious to know why.
Courier, I am also curious about your rating.
Courier mail server (as a whole package) is quite horrible I found (overly complex to point of thinking back to days of COBOL programming and thinking 'it wasnt that bad really') however, the Courier-Imap & Courier-pop packages are excellent. For my large mailservers I use Courier imap & pop, alongside postfix, and they work very well.
I would also be curious as to see why you rated courier so low (it would nearly be worth marking courier components seperately).
I'm not too familar with rest - I try keep away from sendmail due to bad memories, and no reason to try others, so I cannot comment.
Anyways, could be interesting discussion (or flame