Fallout/Allies

Ian

 * Hit points: 50
 * Armor: Leather Jacket
 * Starting weapon: 10mm Pistol
 * What he can use: All one-handed pistols (except for energy), knives, unarmed
 * Usefulness: Very high
 * How to get him: He is in the guard house at Shady Sands. He'll join you for free if you ask about his injury and tell him that you are sorry. Ask him to join you. If he asks for money, tell him that he can have a piece of the action and he'll join you for free.
 * Deadly with: .223 Pistol or 10mm SMG (be careful if you choose the latter)
 * Extra info: He can give you directions to the Hub and Junktown.
 * Pros: Good with one-handed weapons, high small guns skill, not too bad with unarmed weapons
 * Cons: Armor not too great, two-handed weapons pose a problem, he uses spiked knuckles instead of a gun (if you give the former to him), gets burst-happy (like all NPC's)

Tandi

 * Hit points 35
 * Armor: None
 * Starting weapon: Knife
 * What she can use: Knives and Pistols
 * Usefulness: Low
 * How to get her: After you rescue Tandi from the Raiders, don't return her.
 * Signature feature: Probably running away...haven't used her as an NPC
 * Deadly with: Possibly a Ripper
 * Extra info: She can't really talk with you. Also, if you return her to Shady Sands, she won't join you.
 * Pros: Okay at best with 14mm Pistol or Ripper
 * Cons: Low hit points, no armor, and if she's dead there isn't a way to finish the Shady Sands quest.

Tycho

 * Hit points: 60
 * Armor: Leather Armor
 * Starting weapon: Shotgun
 * What he can use: Small guns and spears, prefers rifles and shotguns
 * Usefulness: Very High
 * How to get him: Wait until the evening and enter the Skum Pitt. Talk to him and ask him to join you. You can only recruit him if you agree to help Killian "clean up" Junktown (accept the quest to kill Gizmo).
 * Deadly with: Combat Shotgun or Sniper Rifle
 * Extra info: He can increase your outdoorsman skill.
 * Pros: High small guns skill, can use virtually any small arms, decent unarmed/melee choices, has the best armor out of any NPC
 * Cons: Like other NPC's, he gets burst-happy

Dogmeat

 * Hit points: 50
 * Armor: none
 * Starting weapon: unarmed (teeth)
 * What he can use: Teeth
 * Usefulness: High
 * How to get him: He's at Junktown, just like Tycho. He's messing with this man named Phil. Feed him with an iguana-on-a-stick or walk around him with a Leather Jacket on.
 * Deadly with: Teeth (what else?)
 * Extra info: He can't use items (he's a dog!), and for that matter, can't talk to you. He's very loyal, however.
 * Pros: Lots of action points and high critical chance
 * Cons: He won't leave you until he's dead, and he soaks up damage like a sponge (literally)

Katja

 * Hit points: 39
 * Armor: Leather Jacket
 * Starting weapon: throwing knife
 * What she can use: Throwing Knives, all one-handed pistols (like Ian)
 * Usefulness: Medium-High
 * How to get her: Go to the Followers' Library in the Boneyard and talk to her. Tell her that you don't plan on staying at the Boneyards and she'll join you.
 * Deadly with: 14mm Pistol (I've heard she gets good criticals with that weapon.)
 * Extra info: She can pick locks. This comes in handy in the endgame, especially in the first floor of the Cathedral (if you find Morpheus and his mutant guards too much to bear).
 * Pros: Can lockpick doors, okay with 14mm Pistol
 * Cons: Can't use SMG's well (unlike what she says), fewer hit points than other NPC's, weak armor