HERE maps (aka Bing maps and formerly owned by Nokia) and Google maps are basically the same. Their major advantage is free updates. The legacy GPS services require licenses or subscription fees. By the way, you do not need a data plan or even a SIM card to use GPS. If you don't have data service, you would have to download the regional map you want to use in advance. In the case of the Dominican Republic, the map uses about 20MB of storage. If you have the map on your device, any number of GPS applications can use it to drive turn-by-turn voice directions.
Nothing is free. While Google does not collect usage or purchase fees, it ruthlessly mines your personal data (in the form of your address searches and your minute-by-minute progress along routes, as well as where you may stop to eat or whatever). It's a bigger deal for some than for others. I think it's important to know what you are using.
HERE maps mobile version comes bundled with Microsoft phones running Windows. The online version is virtually indistinguishable from Google Maps. It uses the same personal data mining model to make its money.
Garmin and the other old school GPS devices and services are past their prime. They are still used by rental car companies and in developing regions where many users can't afford modern mobile devices.
google maps with any data plan will be better than any premium Dr map sold anywhere. Google maps are free and come installed in almost all android phones. why even consider buying a map when google gives you all for free?
AZB