While this is slightly generic, is is applicable here.

On Wed, Jul 18, 2018 at 03:07:50PM +0000, Turritopsis Dohrnii Teo En Ming wrote:
> I am torn between deploying Microsoft Exchange 2016 and Linux-based
> SMTP servers like sendmail, postfix, qmail and exim.

It very much depends on your existing user base.  If one exists and it is
used to using Exchange for interoperation (e.g., shared calendars), even
though we can find an equivalent for Linux, they won't be happy because
it's not "how it works now".

> Relative ease of installation and configuration is an important
> consideration factor.

Neither is brain-dead easy to install and configure, although after doing
both for years, I still think the Exchange setup and interaction is more
(overly) complicated.

You can use "webmin" to assist in configuring Linux-based SMTP and IMAP/POP
services, which can reduce the pain.

> Microsoft Exchange 2016, Domain Controller, and Active Directory are
> relatively easy to install and configure.

Well...except you really should have two servers--one for Exchange, one as
your AD Domain Controller.  You could virtualize, of course.

> Linux-based SMTP servers are extremely difficult to install and
> configure and of course, extremely time-consuming.

With all due respect, what?  First, as mentioned, you can use "webmin" to
make the configuration for most simple configs close to automatic, as long
as you understand the concepts of smart hosting, mail relay denial, etc.
Plus there is a plethora of setup guides for both SMTP MTA (e.g., sendmail,
postfix, exim) and POP/IMAP (e.g., Dovecot).

Exchange Servers are time-consuming.  They have a proprietary configuration
and support environment that has a pretty steep learning curve.  Oh, and
don't forget the licensing down the road.

And have we mentioned that it does appear Microsoft wants to "kill off"
on-premises Exchange servers as much as possible, doing a full-court press
on (subscription) Office 365.

> One of the features of Microsoft Exchange 2016 is that you can create
> additional folders on your Inbox in the server (server-side). Can
> Linux-based SMTP servers do that?

Purely a MUA and/or IMAP hosting issue.

> Does Exchange 2016 offer more user-friendly features or Linux-based
> SMTP servers?

Apples or oranges?  Of course there's a bias here in favor of Linux-based
MTAs and MUAs.

> Besides the above considerations, how about security? Traditionally,
> Linux is far more secure than Windows.

An Exchange server can be made reasonably secure.  It requires time
and work.  A good hardware firewall, of course.  Probably 3rd party
anti-spam and malware.

> Judging by security, Linux-based SMTP servers ought to have a higher
> percentage of the market share?

You would have to do research on that.  I believe it's a safe bet.

> Finally, I can only use Windows Server 2016 Standard Evaluation Copy
> FREE for a period of 3 years MAXIMUM. But I can use Linux servers and
> Mail Transport Agents (MTA) FREE perpetually.

Costs for running an Exchange server and AD DC are most assuredly non-zero.

G'luck,
--
        Dave Ihnat
        dihnat@dminet.com