Hey, thanks for the input. 
Originally, I planned on ARB. Then I thought about Marlin's front disconnect. That makes a front locker selectable.
ARB has plumbing and needs an air source,also much pricier. Detroit is self contained.
Which one is stronger? 
I'm running lockers front and rear now, and I can tell you it is impossible to turn the damn thing locked.
it sort of makes it selectable...when you put it in 2Xlow, its just that...low TWO WHEEL DRIVE. With an ARB, you at least have some torque being transferred up front, until you hang a wheel off of something. Actually, I think you are thinking more in line with a twin-stick, which would give you 2Xlow, whereas the disco box would still be a pregnant dog to turn if you put it in front only.
