This information has been collected (and I have learned a lot) by talking directly to the manufacturers of many types of the following differentials. I only used the "brand" names where I thought it would provide clarification...

Based on this list there are actually 8 different types of differentials that you could use in a 4x4... Most of us know them as Open, LSD, and Locker, but upon reviewing this list one can see that there are actually many choices, each of which may or may not have its benefits....

Disclaimer - these are "based" on information from many manufacturers... some information may change or be slightly different in use....

• Open Differential:
  Provides 100% of power to wheel without traction
  0-100 or 100-0 (Percentage Left-Right)
• Clutch or Cone Style Posi (Trak-Loc, LSD, Auburn, Gov-Lock, Powr-Lock)
  Typical application bolts to ring gear
  Provides power split between wheels
  50-50 or 0-100 or 100-0
  If one wheel slips (based on torque) Sends 100% of power to the wheel that has Traction
  100-0 or 0-100
  Fall back problem Is clutch can release on heavy pressure causing slippage or no power to either wheel
  0-0 clutches and cones wear out
  Typically these differentials require a special additive (that most Jiffy Lubes and such fail to put in - which will cause things to wear much quicker).
• Gear Driven Posi or Positive Locker (Tru-Trac, PosiLoc)
  Typical application bolts to ring gear
  Provides power split between wheels
  100-0 or 0-100 or 50-50
  If one wheel slips (based on torque) sends 75% of power to the wheel that has traction, 25% to other wheel - Then locks positively until pressure and/or power is released.
  75-25 or 25-75 ( may be 70-30 or 30-70 but you get the idea)
  Problem is that under even load, wheels may spin at different rates of speed gear can not release on heavy pressure causing slippage (Positive Locking)25-75 or 100-0 or 0-100
• Powertrax No-Slip Differential or Detroit Gearless Locker
  Designed to work in front wheel applications when hubs are not present (will also work in other areas). Application may bolt to ring gear (Powertrax) or replace spiders (Gearless and Powertrax)
  Provides power split between wheels
  50-50
  Power split (based on speed & torque ) will occur on one side to allow cornering 100-0 or 0-100
  Can not release on heavy pressure causing slippage and must provide power to both wheels in a straight line (Positive Locking)
  50-50 or 100-0 or 0-100
• SoftLocker or Detroit Locker or EZ-Locker or Lock-Right (The SoftLocker is the replacement for the original Detroit Locker)
  SoftLocker and Detroit bolt to ring gear, EZ and Lock-Right replace Spider gear sets.
  Provides power split between wheels
  50-50
  Power split (based on speed) will occur on one side to allow cornering
  100-0 or 0-100
  Can not release on heavy pressure causing slippage and must provide power to both wheels in a straight line (Positive Locking)
  50-50 or 100-0 or 0-100
  Detroit Locker (SL or Standard) is much stronger than an EZ-Locker or Lockright Differential. The Detroit Locker (with the exception of the "C-Clip Locker") is warranted for any size tire, or for competition provided the internal springs are not modified.
  Downside tire wear, and noise are common (although from experience the Detroit is actually much quieter then it used to be). There are some strength questions with the Ez and Lockright's and a loud clicking can normally be heard when cornering.
• ARB's or other "Command Lockers" (Toyota Rear Locker)
  Bolts to ring gear
  Switch Off (acts like open differential - see above)
  Provides 100% of power to wheel without traction (based on torque)
  0-100 or 100-0
  Switch On (acts like a spool - See Below)
  Provides power split between wheels
  50-50
  Acts like a spool (50-50 power split until turned off) - There is no differential action. When engaged in the front, turning can become quite interesting. Advantage for turning when disengaged.
  Downside is that they have many more part - air or electrical dependencies external to the differential connections, not automatic.
• Spool (or Mini Spool)
  Spool bolts to Ring gear (Mini Spool replaces Spiders)
  Provides power split between wheels. No differential action when cornering
  50-50 Period
• Lincoln Locker
  This is a modified open differential that essentially has the Spider Gears welded together making it like a Spool.