Google Apps supports the implementation of an extremely secure HIPPA Compliant environment with minimal implementation and support cost. There's no service in the world that can offer the same level of ongoing security per dollar invested.
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!