Google apps is the solution you're looking for.
Google apps covers everything you need for business communication: email, chat, video conferencing, file sharing, wikis. Google apps completely changed the way my business operates.
- Low learning curve... it's custom branded gmail - White label branding - Cheap
- SSO integration is a little fussy sometimes - Limits on branding options. Enforcement of custom themes would be nice. - External file sharing is limited.
Google apps is cheap, powerful, and had the quickest ROI.
Office365 presented a steep ROI, with complex licensing, and users were not familiar with Exchange.
Used for secure internal email communications, file sharing internally, as well as chat.
Google Apps allows for cloud access to our files and emails
Approximately 3 months.
This is what you want, bar none.