Kepler is definitely one of the most important space telescopes that we have (and will have for the foreseeable future). It has both long and short cadence data

Kepler is definitely one of the most important space telescopes that we have (and will have for the foreseeable future). It has both long and short cadence data for many very interesting targets over 3 month periods. TESS will only give us data for one month on each arc of the sky it is scanning (although, it means we'll get a full picture of the sky) but it won't observe the K2 field (the ecliptic plane). It's such a shame to see it losing so much fuel and energy.