I've never found it particularly necessary to tune exim, out of the box
with a basic configuration it handles itself very well and scales nicely
even up to heavy loads.  I've used it in 100k+ e-mails a day
environments without any stability or performance problems.  It's a
rather popular mail server in the UK, possibly by nature of it's origins
at Cambridge.

I've not spent much time using postfix, but every time I have it's been
relatively straightforward and intuitive as well.  Always seems to
perform well too :)

I rather feel its a bit of a case of 6 of one, half a dozen of the
other.  Both tackle the same problem from slightly different angles, and
both have achieved excellence in their own ways.

There is a great introduction to configuring exim on this site:
http://www.exim-new-users.co.uk

Paul

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