10% larger planets on colonization
Most servers have extra 25 oe 30 fields for everyone, which makes this only a minor advantage
-25% research time
Many recent servers have double research speed for everyone, which makes this worthless
But no fleet slots to use them, which makes this worthless
+400% gain on successful expeditions
Is good, but is less good on any server faster than 1 speed as expedition time does not scale with server speed.
With the right server setting Discoverer is OK, but with real server setting it is not