There are about 50 relevant systems that will help a law firm bill their time, invoice it to their clients and "hopefully" produce some meaningful reports to the management. After struggling with one of the standard small business solutions for years (slow, buggy, went down, didn't work between multiple offices, didn’t integrate with the accounting package), one of our clients took a different route. In order to maximize their productivity they asked us to build a custom billing solution for them.
Considering that we are consultants and we bill by the hour or by the project, we are familiar with the requirements. 6 months into the game, we rolled the system out and voila! It was absolutely custom fit to their specific needs.
The vicious cycle of manually synchronizing accounting package with a time tracking package and spending 3 sleepless nights every month to produce few hundred invoices is completely gone. Our biggest challenge was explaining to our users how simple it is to use the system. After years and decades of "abusive" time keeping systems, they just couldn't believe how easy it could be.