Wow! What a deceptively powerful question!
According to the member of the Mustapha Mond's BNW society the savages are those members of the savage reservation who still feel the emotions of pain, suffering, sickness, loss, old age, and still subscribe to very "human" things as nature, books, suffering, monogamy, sacrifice, and religion. Ironically enough, in this particular novel those termed savages (John the savage, et al) are the ones who AREN'T savages and have attained a level of humanity closer to ours and a more "soul-full" existence.
Certainly, some might argue that the scientific, completely controlled and manipulated society of Mond's BNW might have have a "cleaner" society, but they are the true savages because anything that "controls" things against the human will, human spirit, and human destiny seems overtly savage. The reason that John the Savage commits suicide in the end of the novel is because he is reacting against the emotional, spiritual, and physical savagery he experiences while in Mond's BNW. Concentrate on the section of the novel where John the Savage is discussing everything with Mustapha Mond. John the savage argues for pain, for suffering, for the ability to CHOOSE and be FREE.