Oddities about the stat information worth noting:
- DoT is not indicated by the Infection indicators. It stops a good while before the infection "clears".
- All parasites deal ~500 damage when they detonate on an enemy, regardless of variation.
- Individual shots will hit for the damage stated, but every time an infection is applied, a damage burst of ~600 will trigger, and in most cases a parasite will spawn.
- "Bug DMG" actually refers to the DoT applied per infection indicator, up to a maximum of 3x the number shown (3 infections applied)
- All variations will spawn bugs upon enemy death.
Afflictor: "Spawns parasites whenever a target has been hit five times"
This is more or less the same as the standard "Infector" variation. I believe it is bugged (no pun intended), and that it should actually spawn one extra bug per infection indicator (every 5 shots), or 2 bugs per 5 shots. But since it doesn't, it has the exact same stats and behaviour as the normal variation.
Canker: "Does not spawn parasites but infections deal increasing damage over time"
- Does not spawn parasites upon infection.
This has the highest DoT among the variations, but it does not spawn any bugs except upon enemy death.
It shares the shortest range and slowest refire rate of all the variations, along with the Invader. (The difference in refire-rate is countered by it not being burst-fire)
Immunizer:
Has extended range, but other than that, behaves as the standard variation.
Incubator: "Applies a slowing effect to infected targets restricting their movement"
- Does not apply DoT upon infection.
- Spawns 2 parasites per infection.
This relies solely on parasites for damage, and does not apply any DoT. Aside from that, it behaves in much the same way as the base variation.
Infector: "Causes parasitic infection of the target which then burst allowing the release of alien life forms"
The Vanilla version. It applies DoT and spawns parasites upon infection, but has no advantage except having no particular disadvantages.
Invader: "Fully automatic version of the infector allows for quick infection of targets"
This is both fully automatic - as stated - and spawns bugs upon infection. It's DoT is, however, the same as the base variation.
Outbreaker: "Spawns parasites whenever a target has been slain while infected"
- Does not spawn upon infection.
This variation is somewhat like the Canker, in the sense that it does not spawn any parasites when applying one infection mark (every 5 hits). It does, however, have slightly different stats compared to the Canker: It does less damage over time - but more than the other variations, and has a longer range.
So, to sum it all up:
Canker has the highest DoT, but doesn't spawn parasites on infection, and has the shortest range.
Invader has the second highest spawn-rate of parasites, as well as DoT, but shortest range.
Incubator slows enemies, the highest spawn rate of parasites (2 on infection), but has no DoT.
Afflictor is possibly bugged; it spawns 1 parasite on infection like most other variations.
Outbreaker second highest DoT with increased range, but doesn't spawn parasites on infection.
Immunizer has the farthes reach, but nothing else.
DoT:
Canker: 172
Outbreaker: 52
Rest: 34
Incubator: 0
Parasite frequency: (X = Number of active infections)
Incubator: 2 upon infection, X upon death.
Rest: 1 upon infection, X upon death.
Canker: 0 upon infection, X upon death.
Outbreaker: 0 upon infection, X upon death.
Range:
Immunizer: 40
Rest: 35
Canker: 17
Invader: 17