官场 almost always sounds critical: it suggests connections, flattery and self-protection rather than public service, as in 官场文化 'officialdom culture'. To say neutrally that someone works in government, use 从政 'to go into politics'.
Late-Qing satirical novel by Li Boyuan, serialized 1903–1905: chapter after chapter of officials buying posts, taking bribes and fooling their superiors.
