Digital mobile vehicle radios come in two main standards. These are DMR, an dPMR.
Greater spectrum efficiency, allowing two conversations in the same ‘channel space’ is one of the advantages of digital.
Digital radios can also operate in analogue mode, so that you can continue to use them with your existing radios, until you are ready to migrate to digital.
You want digital if call security is paramount, and cost is not such an issue. You want the best!