Google Apps for Business
Google is the market leader when it comes to cloud based business email.
Built for the cloud. Google Apps was designed as an entirely cloud-based service from the ground up, so IT departments don’t need to spend time and money maintaining any desktop components.
The suite includes file storage and sharing with Google Drive, real-time collaboration with Google Docs, video meetings with Hangouts and professional email with Gmail, all for one single price.
With Google Apps for Work, you'll receive a number of additional business-grade services not included in the free consumer product, including: professional email at your domain, additional storage across Gmail and Drive, 24/7 phone and email support, 99.9% guaranteed uptime, interoperability with Microsoft Outlook, enhanced security features, and full administration of all user accounts.