What's the best Office 365 integration solution?

Looking for some feedback on available options for Office 365 integration (yes I’ve looked in the store), I’ve had experince with the official plugin, but it’s not very robust. You can’t create new records, ie: contacts, leads, tasks, opportunities, etc. There is no calendar integration.

I personally use the Opacus plugin on the standalone desktop outlook version and find it pretty great. Is there anything similar for Office 365? Looking for feed back from people who have actually used a solution.