Many threads here and at the outlook.uservoice.com forums indicate that OCM simply does not have properly functional contact sharing - that is, that all staff can see all email history to and from a shared contact.
Many users have commented that MS BCM used to do this just fine (as does our current circa 2003 software). As such, should I be looking to install MS BCM to use with our O365/Exchange Online planned setup? Or should I be looking elsewhere if I need proper contact email history sharing?
Unfortunately, Microsoft has decided to discontinue Business Contact Manger (BCM) so there won’t be a 2016 version of BCM nor an update to make the current version compatible with Outlook 2016. If you are not ready to give up on BCM just yet, you can set a Registry key value to prevent your Office 365 installation from being upgraded to Office 2016 so you won’t run into any issues. However, we don't recommend you do this as Outlook 2016 is more convenient and functional. More and more products will be developed and integrate with Outlook, for what we've seen, you can see that Skype for Business has good integration with Outlook. So it is suggested you use Outlook 2016 and OCM for your business.
We plan to use O365/Exchange Online and had planned to use OCM, however as you can see from the discussion on the thread above, OCM isn't suited to small business where the employee count is > 1. It just fails at proper contact email history sharing in that case.
I'd read many many comments that OCM was supposedly as re-do of BCM, so given OCM still doesn't have functional sharing (and MS Dynamics is far dearer than competitors), thought I'd try BCM in the meantime, with our O365/EO setup.