[CentOS] CentOS 6, Postfix Dovecot

I only have one Postfix server running at the moment and have some 
questions. On that install, I did Amavisd-new with ClamAV, SpamAssassin, 
Postfix and Dovecot.

I know this is a bit off topic, but I'm really hoping for performance 
guidance.

Is the added layer of complexity running Amavis worth the effort on a 
system with moderate mail flow? Or should I just go down the path of 
getting Clam and SA working with Postfix and be done with it?

Whatever path I decide upon now will hopefully be the future for other 
system builds to come. I have about a dozen Sendmail installs running 
(which will eventually need to be moved over). Some of what I didn't 
like about those is Clam/AV and other checks occurred on both incoming 
and outgoing email. We pretty much don't have an outbound email virus or 
spam problem, so were getting a number of false positives due to DHCP 
and clients being assigned a dirty IP address from time to time.

So yes, what's a good mailserver setup which hopefully stays as close to 
upstream as possible on 6.0?

John Hinton