What are the differences between TESS and PLATO exoplanet telescopes? Within a year now it has been decided to launch TESS in 2017 and PLATO in 2024, space telecopes of NASA and ESA. They seem to have very similar science goals, both searching for transiting Earth sized planets in the HZ of the brighest (nearest) stars across all or most of the sky. 

Are these missions as overlapping as they seem on first sight, or are there important complementarities? Is it perhaps the intention for PLATO to continue the observations of the planets discovered by TESS in order to get a longer time series?
Here is what one commentator has said about TESS in comparison to PLATO:

The Transiting Exoplanet Survey Satellite (TESS), to launch in 2017, seems superficially to be a similar mission to Plato. It will potentially discover hundreds of planets before Plato even gets off the ground in 2024. However, the limited sensitivity of its cameras mean it is completely blind to Earth-like worlds around sun-like stars. Astroseismology is also off-limits for TESS, meaning the size of any worlds it does discover will be highly uncertain. Unlike Plato, it will also move between patches of sky every 30 days, allowing only hot, short-period planets to be found.
With all other new telescopes, both in space and on the ground, limited to finding super-Earths around small stars, Plato is the only mission on the table truly capable of discovering an Earth-like world around a star like our Sun. And by targeting bright stars that allow atmospheric follow-up, it is not impossible to think that, as well as the first truly habitable planet, Plato could find the first inhabited one too.

Credit: Hugh Osborn, PhD student, University of Warwick

http://lostintransits.wordpress.com/2014/01/30/what-can-plato-do-for-exoplanet-astronomy/