My Sova actually got showed a good time during my first Pirate Invasion. Lost the planet (My fleet was 4 jumps away), and during the battle I lost 5 frigates (3 Cobalts, 1 Hoshiko, 1 LRM) and that was... it, actually. The only thing about the pirates that scared me was that they knew where my least defended planet was, and how to get to it. (They even avoided the starbase I set up to intercept a direct jump away from the Pirate Base, they went to the star and around the Starbase) That, and their Cap Ships.
Also: This may be a glitch, but I just conquered an enemy Urban Planet, and about a minute later the Pirates Raided the same enemy that I just beat. So, they jump to the planet I just took. I figured that they would just go to the next enemy planet, so I docked my SC and waited. Well, as it turns out they did NOT attack the target I paid them to attack, they attacked the planet I just took!