Unless you only drive on dry pavement, or at high speeds regularly, I would get a locker. I think if you got a LS you will wish you had a locker. If you do drive mostly at high speeds you could get a selectable locker, if most of your driving is at lower speeds a auto locker might work for you.
I have had a lockrite auto locker in my truck that I drove 400 miles a week since last fall, and have liked it, Now when I hit a spot with poor traction the locker will keep me moving through stuff that would have stopped me with an open diff. I also can run at a slower speed with out having to rely on momentum as much as before. It is also much easier to get moving in slippery conditions.
I have had it on snow covered roads, muddy back farm roads with ruts a foot deep, and wet/dry paved roads. I have driven up my gravel driveway that was covered in slushy snow and ice that a fwd minivan with identical winter tires could not drive all the way up. In the past I always had trouble getting moving if I had poor traction conditions. Last winter the only time I had difficulty was starting up hill from a stop sign on polished ice in a sams parking lot, I was still able to get moving up the hill however.
The only things I have noticed is that at speeds over 65mph you do get some noticeable squirming when you get on or off the throttle, my steering has a little bit more play than I would like and could be making the locker more noticeable at 65 mph, also at some on ramps I can feel it pushing towards the outside of the turn. At speeds under 60mph I do get some slight squirming when getting on or off the throttle, however if someone else not familiar with my truck drove it they probably would not notice. I can only faintly hear it ratcheting when turning tightly on pavement with all windows open and the radio off, if I have the radio on I can not hear anything. It does not seem to be wearing the tires unusually. It was very easy to get used to, and after maybe a week of driving I hardy notice it anymore.
In the future any truck that I plan on owning for any length of time will get a locker(s).
the lockrite installed very easily in a couple hours, I got my lockrite from
http://www.trsfabandoffroad.com/products/lockers.htm I think it was around $356 shipped + around $30 for new synthetic gear lube
you should be able to figure out what axles you have from this link in the tech library
http://www.therangerstation.com/tech_library/Axles.html