There are currently over 750 D-STAR repeaters in the US. During the 2014 D-STAR QSO Party (held in September each year) over 1,000 hams were on the air from 36 countries. The ten winners received an ID-51 50th Anniversary Edition HT.
This gives you a flavor for the broad reach of D-STAR here in the US and around the world. What I like about it is being able to talk with anyone throughout the world without being at the mercy of the latest sunspot count.
For example, when I was on a DX-pedition to Mozambique a few years ago I was also able to use D-STAR to talk with many Scouts who were on that weekend for Jamboree on the Air. We had reliable clear communication without the pileups and QSB/QRM etc. And, what a blast to talk with Scouts about amateur radio, their current campout, local weather, etc.