Barkley Advertising, headquartered in Kansas City, MO worked with Google Enterprise Partner Umzuzu to move 235 employees from Exchange 2007 to Google Apps for Business in the fall of 2011. Barkley IT Director, Steve Covell, and Network Engineer, Kevin Buller, looked to Google Apps to solve their cross-platform and space challenges that have persisted since computers first entered Barkley in the early 80s.
If your employees are leveraging Dropbox to get work done, you should give them Dropbox. More importantly, you should control Dropbox in the same way the firm manages other technologies - email, calendaring, the phone system, laptops, project management, Word, etc.
Umzuzu is a small, bootstrapped firm in the Kansas City area. Certainly year 11 is much easier than year 1, but we never forget our roots. We understand the desire and value of the DIY projects. They can often save money, especially initially. But as we all know, DIY projects can be surprisingly complex!