Sounds like I ruffled some feathers. That was not my intent.
To be fair, the cost varies wildly depending on industry. My company does a lot of management and support services of customer-owned on-premise systems in the 501(c)(3) arena. Charity/non-profit pricing from Microsoft is pretty much a give-away to qualified entities, subject to quantity limits. So speaking strictly in regard to non-profits, the minimal acquisition cost of Exchange makes it cheaper than SM, with no annual support renewals needed to retain EWS/EAS/MAPI functionality. SM is a tough sell in that space.
Quite the opposite, in the FOR-profit arena Exchange is monsterously expensive, so we're thrilled to see MAPI coming-- to give us a solid Exchange alternative with our for-profit corporate and SMB clients.
EAS with Outlook has been a hard sell. Honestly, it has. Most of the customers we've put on EAS ended up cancelling the option, and went back to IMAP with CalDav. EAS bugs were part of the reason (duplicate calendar items, etc.), the upsell cost was another. We have a bunch of EAS licenses going to waste. Even when we've given some of our preferred customers free trials on EAS, nearly all ended up sticking with IMAP/CalDav after the trial.
To its credit, SmarterMail is much easier to manage. Exchange is bloated, a RAM glutton, and the databases consume tons of "white space" on disk that cannot be reclaimed without offline defrags. We've had the occasional database spontaneously dismount, or refuse to re-mount after reboot, that no amount of repair attempts would cure. Recovering a DB from backup has sometimes been the only option, with the obvious loss of new emails. And despite Microsoft's hype, the web-based Exchange control panel (ECP) that replaced the Exchange Management Console, just plain sucks. I would much rather manage SmarterMail servers.
With that said, I stand by what I said about the optics of add-on fees. To get near the full-on Exchange experience, we'll need to purchase at least 4 separate SKUs, and renew them each and every year: SM, EWS, EAS, MAPI.
I get that many customers only want SM and nothing else. But perhaps in the future, you could offer a package that bundles SM, EWS, and MAPI into a single SKU, with EAS being the only add-on? Other than mobile devices, that single SKU would pretty much handle everything needed to hosting clients on Outlook, Apple/Mac Mail, et al.
Just a few thoughs, from someone who's been a happy SM administrator since version 3 (circa 2006).