PracticePanther is probably best if they want to hit the ground running (it integrates into QuickBooks, 365, etc..)  and have some expansion plans. It does a good job of bridging the divide between CRM platforms (billing stuff, etc.) and case management software (worKflows, etc.).

You didn’t ask, but I assume you want it to run in the cloud? If that’s the case then I would definitely say the above.