Some IHS sites are wonderful, others are almost like war zones where all staff have a 'bunker mentality.' Appalachia as well is a traditionally underserved area. If you are the sort of person who could be happy in a very small town, it is an excellent option.
And btw not all the sites are 'sinkholes.' I had the opportunity to rotate at a USPHS site and was blown away by the quality of the doctors and their dedication (not that brand name is everything, but two of my attending had done med-peds at MGH-Boston Children's). Many had worked at that particular hospital for 20+ years, they were so dedicated to the population. I got added warm fuzzies for feeling like I was truly taking care of people who had literally no other resort, and-- as someone going to school in NYC-- the chance to be the 'only shop in town' was amazing. I had days where I literally did everything there is to do in medicine-- delivered babies, ran a trauma code, sutured up lacs, outpatient adult and pediatric medicine, rounded on my very sick inpatients.
This is in clinical medicine-- the only strict public health opportunity I know of is the EIS, which is awesome of course.