I will share my latest experience with a customer with some 725 GB of mailboxes on 58 users. Some users having more than 70,000 mails in their inbox.
Users having mailboxes bigger than 5 GB we basically gave up on EAS, as it never got done synchronizing (the customer have a 100/100 connection), so we switched users with issues on EAS to IMAP, but then another problem is showing its ugly face, the calendar and contacts are not synchronized and we have to map a sharepoint list to those. But we are still missing notes and tasks. And users on IMAP experience up to 5-6 minutes delay on receiving their emails, and they notice because their phones have had the mail for that time before it arrives at their desktop pc.
Even though we have mapped the calendar with Sharepoint it do not work when a user receives a meeting request, as upon accept the appointment is not added to the SmarterMail/sharepoint calendar but the default calendar so no sync to mobile devices for this user. I have to say I got a link from ST to a CalDAV add-in to outlook and it looks promising so far.
But what about Tasks and notes have anyone cracked that one?
We would prefer to be able to use EAS, and if MS can get it to work with +50GB mailboxes why are ST not able to make updates to their system so we can get it to work...
We also have issues with calendar appointments being pushed forward 1 month on recurring events after we migrated from Exchange. Reminders are completely lost. We have at least one confirmed errior with an appointment being pushed forward 1 day, so the customer almost missed a meeting with clients from Singapore.
Any information if anybody has cracked the issues above would be highly appreciated. We would like to stay with our SM. It works beautifully as long as mailbox sizes are under 5 GB, but big companies sometimes have serious big mailboxes, so we need solution for those.
I hope issues like this would be resolved in the upcoming SM15, so we dont have to wait for SM16 to get bigger mailboxes to run with EAS. We would love to see more Enterprise features implemented before the competition (MS) have captured all those customers.