Pirates: Bad
Rebels: Generally good
Confeds: Kind of bad in principle, but they're still nice enough to traders, so they get a 'decent'
Aliens: Incredibly bad
Pirates again: Bad
My favorite EV plug-in so far is 'Galactic Scourge'. It even has its own theme music! Plus a lot of systems, additional ships for all governments, new governments, pretty good storylines, new weapons, more aliens (some of them I would rate as 'Generally good'), more pirate ships even.
'rEVisited' is one of the best plug-ins for EVC for Nova.
Heavy rockets have good range and do good damage, but they sure are heavy!
Neutron blasters are only worth it on the big capital ships.
Pirates are bad (again).
If you can't beat the aliens, try to get a tractor beam. It really helps.
Tractor beams slow down the turn rate of the tractored ship.
This post is pretty long.