There are a lot of Email Platforms in the market, but for businesses the most feature rich and stable platform is Microsoft Exchange. Exchange offers fully synchronized Email, Calendar, Contacts and Tasks amongst all of your devices.
Microsoft Office365 Hosted Exchange has an extremely affordable price and provides all the features and functionality that you would get if you were hosting your own Exchange on a local server.
N2M Technology is a Microsoft Cloud Partner and sells and migrates you from your current platform to the Office365 Hosted Exchange platform.