[CentOS] Which is better? Microsoft Exchange 2016 or Linux-based SMTP Servers?

>
> In addition, if you go to 365, you are NOT BUYING the software, you're
> renting the service. You will be paying every year, and a service contract
> will cost, and, presumably, cost more every year.
>

Still a lot better than trying to run your own hodge-podge of nightmares on
Linux.