So what we've discovered so far in a nutshell:
Sera = Painkiller makes you a PVM God. Run around Magma 2 all day long picking up loot and never die or use pots. You only have to worry about MVP skills rather than attack damage for the most part. Needle of Paralysis is like an Ankle Snare that you can aim and poison mist allows you to mob decently as well while leveling the homunculus. She also has funny bees you can play with.
Eira = Her AoE and damage sucks compared to other homunculus S, but she makes up for it with some interesting tools. Overed boost is very useful. Makes her into a beastly flee tank, makes the genetic into a decent emp breaker in a pinch without being reliant on ANY gears or buffs, and allows farming of intimacy in order to use skills like self destruction more frequently. She can revive you after death, but it's not practical.
Dieter = It does a bit of everything and is possibly the strongest mob-killer of the lot under the right conditions. It has the lowest attack speed, but the highest HP and SP modifiers. Is a piece of crap until lv 109, after which it becomes a machine after learning Lava slide. At lv 123 it basically becomes a ghetto reflect damage RG with Magma flow. Volcanic ash is a nasty, nasty skill that with griefing potential written all over it, as well as possibly being a major pain in WoE precasts for both friend and foe alike. Pyroclastic gives fire endow, ups bomb/cart cannon damage, and makes Dieter's AOE skills even more deadly. It's not as tanky as Bayeri or Sera, but it kills things while it's tanking.
Eleanor = no Aoe Skills at all, lowest SP mod. Awe-inspiring single target DPS. She's like a combo monk in your pocket. She can stop targets from moving and drain SP. Heavilly speciallised towards PVP.
Bayeri = HP tanking and direct caster AOE type skills, and a safety wall skill that's still of dubious use. Needs more research done. Seems that most of it's good skills are interruptable. It's either going to be tanking for the genetic, or attacking safely with it's AOE's while the genetic tanks. It does holy damage, which is kind of interesting.
Actually it's not really the SP drain ( from the limited testing I did ) of C.B.C. that is the really painful part.... tested it on a 150 fully WoE geared sura, one cast 10% SP damage but over the couple seconds he was immobilized it drained 40% HP. with E.Q.C. supposedly there will be an extra 10% ( maybe more, that is the desc. on wiki ) and -25% weapon ATK and -25% DEF ( unknown yet if it is total DEF... I.E. all reducs or if it is just armor DEF ) the 10% SP drain is not that much, but several casts of C.B.C. should realistically drain all the HP from a character. From the one test I did on my sorc the second cast on her the drain killed her.
