With a Detroit you will never lose traction, it is a fulltime automatic differential that will never allow an axle shaft to turn slower than the ring gear (but it will allow a freewheeling axleshaft to spin faster than the ring gear when you are going around a corner).

The ARB is manually operated so it is an open diff when it is off and a spool (no differentiating) when it is on. It is better on the road (and some places off road- like off camber) but is also more expensive and because it is more complicated there is more potential for something to go wrong.

Another option is a factory electric locker from a TRD Tacoma or 4Runner. These operate like an ARB (manually controlled) but cost slightly less and do not require any air lines.

I run front and rear Detroits in my dedicated trail rig for simplicity, ARBs in my daily driven 4Runner for no quirky handling, and factory electric lockers in my FZJ80 (came with them from the factory).