Way too much debate on locker vs welded vs selectable.
My opinion for the rear: (like it matters)
If you are using it as your daily driver and/or on long road trips to get to and from your offroad destination, I recommend a selectable locker.
You will save money in the long run by not wearing down your tires prematurely on the street.
If you use your vehicle for local wheeling or trailer it to your offroad destination and it isn't your daily driver, go with a full time locker or weld it if you are on a tight budget.
I have a detroit locker in my 1986 Chevrolet M1008 CUCV and it does affect turning radius on pavement and eats up the tires quickly but is great offroad.
I have also welded a Ford 8.8 and Chrysler 8.25 with good results.
I am installing an Eaton E-Locker in the '87 XJ Dana-44 that is sitting in my shed to be used in my '91 YJ this time around.
A selectable locker works much better for long trips and overall drivability. They aren't cheap though.