My 2 cents: most of our user`s gripes is with the interface, so I guess that this can be endlessly improved - it just takes some time and will from SM team (and I guess their first priority right now is with the back-end); most can probably be easily improved.
But I personally can see a nice improvement on the mail engine itself, which is why I`ve decided not to give in to the complaints and instead find temporary work-arounds until the interface issues are fixed. We have ~ 200 user accounts (at least half constantly active at the same time) on a decent server (nothing to write home about: a VM with 8x Intel Xeon E5firstname.lastname@example.orgGHz CPU cores, 16GB of RAM, 10Gbps NIC, 2x SSD storage in RAID-1 and Win Server 2012 R2) and server performance is fine - at least just as it was with SM 15. RAM and CPU usage are higher, but only with ~ 10-15% higher and it does not look like a problem. The benefits I`m seeing are:
- a bit better SPAM control (although I complain about the missing response time counter for RBLs) - we`ve seen a sizeable decrease in SPAM
- all of our users have mobile devices (Android, iOS, BlackBerry and Windows Phone), as well as tablets and they all sync their emails at least with their mobile devices. Many do it though IMAP, but at least 80 - 90 connect through ActiveSync constantly. Moreover, at least 30 use constantly MS Outlook 2016 configured though ActiveSync and have quite large mailboxes. We`ve had so many issues with ActiveSync on SM 15 that if v16 would not have come out when it did, we would have gone back to MS Exchange or to Office365. ActiveSync works so much better now (still has some issues with MS Outlook, but not as bad; it`s pretty much perfect with mobile clients, even Outlook mobile) and this really helps our users.
- it`s easy to update and configure (even with the interface change, it`s still worlds better than many other systems, including MS Exchange)
Of course, every case is different and I understand that many have issues - but we`ve actually been though a lot and I do not remember any major system change where there were no issues and complaints and people that just wanted their old ERP back, their old DMS back and so on. What I want is for issues to actually be solved and I can see that SM is working around the clock to fix many things, but probably the change was just too big for them to work on all the problems. Although I think that if they worked a bit more on making the interface more usable and functional instead of "pretty", 90% of the complaints would go away. Take Advanced Search for instance - most users prefer using Outlook (the desktop client or the mobile one) to the WebMail just due to this, but most of them can and do use the WebMail while physically present at work.
I would really like to see something of a time-line or roadmap from SM that would outline their current priorities or areas of focus, so we would not bang our heads on this wall and hope something comes of it.