(Although the Postfix config files are no walk in the park either.)
[1] https://www.oreilly.com/library/view/sendmail-4th-edition/97...
I've never regretted running my own server, nor have I ever contemplated moving to a hosted solution. Spam is not a problem either, Spamassassin in combination with a greylist make for a nearly spam-free experience. The whole setup has been migrated from the original Pentium-66 via an aBit-BP6 (SMP for the masses [2], retired in 2009) to the current Intel SS-4200 (upgraded to a dual-core Pentium but still limited to 2GB). In practice a Raspberry Pi would be enough to run a viable mail server so even this rather anaemic setup does its job without breaking a sweat.
The whole setup consists of Debian (Sid) running Exim through a smarthost, feeding through Spamassassin + greylistd into Dovecot. Apart from some auto-manual intervention to cope with Microsoft/Google/... not coping with the greylisting and thus needing whitelisting it more or less just works. In other words, just go ahead and run your own server.
[1] http://shop.oreilly.com/product/9780596510299.do
For instance, the [sendmail bat book](https://www.oreilly.com/library/view/sendmail-4th-edition/97...) originally talked about all sorts of ways to deal with resource limits, particularly memory, because this was often an issue with servers in the early '90s. Later, memory became cheap and huge, so discussions about this were removed from later editions.
Even when memory ceased being a limitation, though, learning about how to monitor and what to do about heavy resource usage remained important, so the removal was an overall loss. I wish that O'Reilly would make available for free the things they removed from later editions.
I wish I'd've had the money and space to buy the original editions of many of the animal books. I figured they'd live at the bookstore until I did, but then bad things happened, and now bookstores are rare. Perhaps one day I'll find some.