I know it was said that this was on the agenda, so here's a thread for discussion.
I'm going to start with my impressions of the various guardians I can remember - please try to avoid nitty gritty details for now, and just give impressions.
Broken:
Laser Guardians (Biggest offender)
Warp Guardians
Flak Guardians (borderline)
Zombie Guardians
Currently Balanced
Beam Guardians
Tractor Guardians
Sniper/Spider Guardians
Implosion Guardians
Raider Guardians
Artillery Guardians
Tachyon
Special Forces
Underpowered:
Electric Guardians
Unknown:
EMP Guardians
Suicide Guardians
Vampire Guardians
Gravity Guardians
Laser Guardians I view as the biggest offenders because they're fast, good hitpoints, high armor, awkward armor type, rapid fire, multishot, high damage, high range, bonuses against light (fighters) and polycrystal (bombers). Fighters and bombers they pretty much instakill. They're also very common. If I'm going to take casualties, it's definitely these.
Flak Guardians are borderline because they have huge numbers of AOE attacks. I've seen them chew through bomber hordes in not very long. Thankfully fighters deal with them pretty handily.
Warp Guardians are just insane - I've seen some (can't remember which mark) with 32,000x30 (or something like that) attack and 64 million hitpoints. It's just ridiculous the amount of damage they put out and the amount of damage they can absorb - one of them almost soloed my home command station that was sitting under 4 mk1 forcefields.
Zombie Guardians are like laser guardians, but worse, since not only do they instakill what they shoot at, they turn those into zombies. They should probably be more like the leech starship of old (without the marking ability) - low-mid damage, mid-high number of shots. Not good on its own, but worked into a group of ships and it has a high potential to deliver a lot of finishing shots.
Electric Guardians I think are underpowered because they're uncommon, easy to kill, don't do much more than 8k per shot (every 20 secs or so?). Even if they've got a ridiculous number of ships to shoot at, 8k damage is generally not going to make an appreciable dent in most targets (laser gatlings being an exception). I fear these the least, generally.
Edit:
Gravity Guardians are, I think, going to be a tricky issue. So long as they don't spawn too often, I think they'll be okay, but I think there will end up being a number of player complaints about these simply because of how they lock down EVERYTHING. At mk3 I think they hit something like a 10k radius down to speed 8 or so, which is a bit of a nightmare. Then again, you should generally be aware of their existence, so getting caught by one is either going to be gross negligence, or getting really unlucky with having one included in an exogalactic wave, in which case you're screwed until your turrets can deal with it.