Monty,

As an MCP Exchange tech, I can support your cause, but I need to let you
know that some of your arguments are empty.  

First, you need to avoid using the term "POP" to refer to your present mail
system.  Exchange includes full POP support, and with that your whole
argument will be lost.  Because it offers both POP and IMAP support, it can
server mail to any client OS.  It also includes a web interface, meaning any
web browser can access most of the Exchange/Outlook services.

Second, Exchange's mail protocol is similar to IMAP, and the ability to
store the messages as a database on the server is a great advantage.  It is
extremely efficient and reliable, and it performs better than any IMAP setup
I've seen so far.  Bandwidth and network load will not be an issue.

Now for the good stuff:  Exchange is an extreme resource hog.  Running a
stripped configuration with mail for two - three people uses ALL the
resources of a server that was state-of-the-art three years ago.  Nightly
database maintenance currently takes so long that there isn't time to do
backups too, although if the system were only available 8-5 I could work out
the timing.

For many features of Exchange, for additional features like Norton
Anti-virus protection, and possibly for even basic function in current
versions (post-5.5), you MUST install IIS, the other biggest security hole
on the network, and the other biggest resource hog MS produces.  I couldn't
run it on the server I have, it would grind to a halt.  (Which many of the
Exchange servers I've worked with did anyway on a regular basis, for no
reason we ever found.)

If you want dial-up access, you will need a separate server to handle the
logins.  Running MS RAS and Exchange on the same server is not practical.
For a full MS implementation, you will also need a separate PDC, separate
BDC, and separate WINS server.  Even without RAS, that's a minimum of four
licenses for NT Server.

And there's the real argument:  Licenses.  $50 - $250 per accessing client,
even if they're not running an MS OS.  Ten times that per server.  Everybody
who connects to a server, no matter what OS they're running, must have a
separate MS Client Access License.  MS's policies are that these licenses
will only be good for three to five years, after which support for the
software you've "bought" will become increasingly difficult to find.
(Example: try to get support for the Microsoft Mail SMTP server that used to
be available for free download.)

And, of course, Exchange/Outlook is worm meat.  The biggest security hole on
the internet.  The cause of many outages.

RoadRunner KC used a cluster of MS Exchange servers for their email.  They
attempted to install an update one night, and had one of those notorious MS
problems where the update continues to run for hours without completing.
When they finally surrendered to the realization that it wasn't going to be
done in time, they discovered that they were unable to bring the cluster
back on line.  With full, top level support from Microsoft, they were unable
to restore mail service for about two weeks.

The company I currently work for runs Lotus Notes for most of it's mail, but
a few branches run Exchange.  Those branches are overrun with worms and
viruses, the servers coming down on a regular basis because of the latest
exploit.  The only reason I can think of that they don't just all the
servers in the river is because they've invested a massive amount in
licensing and have to amortize it before they can replace it.  Our
non-MS/non-Exchange network segments probably devote 10% - 20% of their
resources to protecting themselves from those segments that run Exchange and
Outlook.

I think that your argument that you are trying to sell Unix servers and
should set an example with Unix based mail is a good one.  I think as a last
resort, you should hold out the suggestion that they not pay for the MS
licenses without a guarantee that if they're not able to maintain a
satisfactory level of service they will be able to recover that money.  No
MS vendor's going to agree to that, so it may save you.

Did we mention that Exchange servers are a major security hole, and the fact
that you practically have to install IIS means they're offering the two
worst security risks on the network?