Upgrades, Migration and Maintenance Issues
Microsoft is smart enough to withdraw support for earlier versions and don’t support version 5.5 anymore, but IBM has always offered comprehensive support for migration, upgrades, and integration as well as support for earlier versions, and they continue to do so.
Furthermore, the IBM Lotus Domino 8 not just offers a messaging solution, but rather a comprehensive combination of e-mail, Integrated IM & presences awareness, contacts, forums, development tools, calendaring, and team spaces.
You get just the bare basic messaging solution with MS Exchange 2007, and you have to pay for anything extra that you may require – after all it is Microsoft, so you can’t expect any freebies from them.
Lastly, the maintenance is rather tedious and time consuming with MS Exchange 2007, while you can just install IBM Lotus Domino 8, and forget about it.
Today, it is just the user-interface and easy of usage that forces many of the customers to go with MS Exchange 2007, otherwise Lotus Domino 8 is far superior to MS Exchange in most aspects including pricing.