The Darwin and Terrestrial Planet Finder missions, represent the European Space Agency (ESA) and NASA's interest in ultimately searching for and when found studying planets similar to the Earth-like planets in our own Solar System. As such they may be technologically very challenging space missions but recent developments points towards robust solutions. In this talk, we compare the technologies, the available solutions, and the current status in both projects. We put the emphasis on the optical technologies required, and address both main possibilities considered for planet finding, i.e. a nulling interferometer and a coronograph. We outline the strategies for selecting the appropriate technology for each element of the missions. Finally we also address the synergy in the technologies required for other missions, as well as other applications except purely scientific.