If memory serves, it gives you 3 experience each time you run into it.  Three or four of them are enough to get your flagship leveled up once or twice once you upgrade it to a low tech weaponized ship (experience required for next level is based on attack + defense total of ship in question), but in all honesty you're better off running around killing whatever the AI produces (as experience gained is dependent on attack + defense of ships killed).

The +4 hp anomalies are far more valuable, particularly before TA's hp modules are easily accessible or worth the space (also in DL/DA).