It's like any other modification, it depends on where you live and how you use your jeep. I have a 2003 with 35s, a 5.9 v8, 4.56 gears, hp Dana 30/ Dana 44 combo. I currently run an open front, trutrac rear. It works well for me. In the summer, it's just cruising around easy trails, sand dunes, etc. In the winter, we like to play in the snow. A couple of my friends run lockers front and rear and hate them. They can not keep their jeeps on the trail. The locked front just pushes around and you cannot control it.
I am going to add a trutrac to the front this fall hopefully. That's what works for me.
I totally get that lockers rule in the rocks. Like I ( and many others) have said, what do you want to do with the vehicle?