Bulletproof Fighters - balanced/overpowered: generally better than normal fighters so it is at the least balanced, but not one of the super ship types
Tachyon MicroFighters - balanced: the 4.046 changes make them seem ok
Raiders - balanced/underpowered: haven't used these for a long time so this might be off, but these things are really fragile require some micromanagement to use properly to take advantage of their long range. Given the current state of the game (where you just mass up a blob of death), proper micromanagement isn't going to happen, and their fragility makes them not that useful.
Parasites - Currently being discussed.
Vampire Claws - Underpowered. When the patch that made command stations immune to vampire claws came in, these guys became close to useless. If that has changed, then I will have to reassess.
Raptors - Underpowered. Being blazing fast is useless if you do no damage.
Snipers - Dunno, haven't tried since latest balance changes.
Space Tanks - Balanced
Electric Shuttles - Balanced
Vorticular Cutlasses - Underpowered. Just don't see much of a use for these.
Infiltrators - Dunno
Eye Bots - Underpowered. Jack of a few trades, useless at all.
Spiders - Balanced. And fun.
Laser Gatlings - Balanced/Overpowered. Good solid ship.
Autocannon Minipods - Underpowered. Don't seem to do enough damage.
Deflector Drones - Dunno
Space Planes - Underpowered. Like most cloaking specialist ships, they just can't compare to starships when it comes to sniping/raiding things.
EtherJet Tractors - Underpowered. Fun but ultimately not useful.
Force Field Bearers - Overpowered. No explanation needed.
Armor Ships - Balanced. And boring.
Anti-Armor Ships - Balanced
MLRS - Dunno
Munitions Boosters - Balanced
Teleport Raiders - Balanced
Teleport Battle Stations - Overpowered. Defensive powerhouses.
Zenith Remnant Unlocks
Zenith Bombardment Ships - Balanced.
Zenith AutoBombs - Balanced
Grenade Launchers - Dunno, been too long
Zenith Electric Bombers - Overpowered. Tough things that don't die are all very powerful (ie starships and things like starships)
Sentinel Frigates - Balanced
Zenith Mirrors - Dunno
Zenith Paralyzers - Underpowered. They always seem to die like flies.
Shield Boosters - Dunno
Zenith Beam Frigates - Balanced
Zenith Chameleons - Balanced/Overpowered - extra bombers are always good
Zenith Polarizers - Balanced/Overpowered - ships that take down big things are always good
Zenith Viral Shredders - Dunno how they work now. Several patches ago they were definitely overpowered since you ended up with thousands of them.
Impulse Reaction Emitters - Dunno
Acid Sprayers - Underpowered. Worst ship class in the game maybe?
Children of Neinzul Unlocks - all underpowered. They all require way more planning and micromanagement to use properly than normal ships. Don't see any proper reward for the effor of setting up regen chambers/transport chains/mobile ship factories.