GH is in a "sterile" tourist designed area of Bali down at the Southern tip of the island. If you are just looking to stay put mostly and not venture out to experience much of Bali you will be fine there. Accessibility is okay (no problem getting Grab or Bluebird), but not great and going to places like Denpasar, Seminyak and beyond like Ubud will be a bit more of a haul and you'll face more traffic jams. Also restaurants and all there are some in Nusa Dua but not a huge selection (outside of other resorts).

HR is in Sanur, a well established and a more connected area that is still geared towards tourism, but not so crazy like Kuta or such and not so isolated and cordoned off like Nusa Dua. Lots of restaurants and lively local life and culture.

Beach not awesome in either area in my book, but probably Nusa Dua a bit more cleaned up around places like GH. Neither one is bad, GH as a resort is bigger. HR got nice grounds and Andaz is next door as well. Just comes down to personal preferences.