Are there even any DStar or C4FM repeaters around you? Just because you have a "digital" radio doesn't mean you'd be able to utilize the network. I have DStar and DMR equipment and it's definitely an acquired taste, it's kind of obtuse to use. Just to plant the seeds of doubt, for the money I would rather have a true dualband radio over any digital mode.
Given any of these radios aren't capable of weak signal modes, the antenna you'll get the most use out of will be an omni vertical. A diamond or comet in a physical size you can manage would get my vote for your Antenna: ? You didn't mention your feedline run so there'll be a performance/cost tradeoff there too.
Mark K5LXP
Albuquerque, NM