MegaWarp has an article about the importance of recognizing sub-genres among space games. It explains why they shouldn't be directly compared with each other.
Occasionally people and the media stubbornly compare space games like Jumpgate Evolution, Eve-Online and the more distant cousins Star Wars Galaxies, Stargate, Star Trek etc.
At first glance they all seem similar, due to the space sci-fi theme. People who are unfamiliar with this will easily put them in the same box.