There are a number of ways to look at the Return on Investment for msg2you, but the best rationale would be the same one that exists for the Blackberry and other "push" technologies - the ability to have real-time access to your internal communications. This means that you will have more timely knowledge of messages being sent to you, and will be able to respond in more quickly to situations that need you attention. This will result in

• Being able to work on issues during otherwise wasted time - while waiting in an airport; from your car, home or hotel with a cell phone call; while waiting outside a courtroom, etc.
• Better responsiveness to your client's needs increases client satisfaction which leads to additional work from that client and others.

At $100 per year, all you need to do is pick up a half-hour of otherwise non-billable time and the license pays for itself.