Integrated microwave photonics has become a topic of considerable research, due in part to the breakthroughs in photonic integrated circuits for industrial telecommunications. A critical assessment of this trend is presented, including important considerations that are lacking in the emerging integrated microwave photonics community. The design space for microwave photonics is reviewed in the context of the “link on a chip” concept. Niche application areas for integrated microwave photonics based on optically coherent techniques are highlighted.