I know for a fact lockers make the world of difference. I had a an Eaton E-Locker on my Colorado that had a 5" suspension lift and that thing could climb and cut through mud that heavy F150's and 250's would get stuck in. I was not the one pulling them out because I was too light but I always had a good time.

Once I get the 1K to get the upgrade for my D44 saved up I'm going with eaton.

 

Honestly Im up in the air on this as well. Even though I dont have a locker in my 2012, I do have the Trac Lok option. Which is not esp. It is totally different. I didn't even know my jeep came with this. On my last trail run I found myself doing a little better than other jeeps with open diffs. A buddy asked if I had lockers. I said no, he said it looks like I do.

In my old 07jk it was open diffs, and I honestly kept up with locked rubicons no problem.

On my old Tacoma, I had the rear locker. And I found my self having to use it in a few situations. Even though my old 07 jk had open diffs, it climed obstacles better than my much more trail ready Tacoma did locked.

Although I have noticed, Taking my new 2012 with trac lok on the same trails, it performs better.

CLick link and forward to 2:04 min and you will see my tacoma locked do a steep climb.
TacomaWorld Colorado (Full Video) - YouTube

Here fast forward to :50 sec and see my 2012 jk with trac lok climb it much easier.
Jeep JK Off Road "THE COLORADO JEEP PROJECT 2012" - YouTube

Although I noticed a buddy of mine with a 2 door rubi first attempted that climb with open diffs and struggled. He threw on his lockers and climbed right up no problem.

Soooo all in all, I would say a locker really is worth it on a Jeep. Useless in a tacoma

 

You hit the nail on the head sir. I think the OP needs some more real world experience.

 

I have a 13 Rubi, with lockers engaged, it is true four wheel drive, as long as you turn off traction control. All four tires will turn. ESP will not effect them if off. I would put my lockers ( and have , in black Texas mud ) against any aftermarket locker. I have driven mine through things I would not have considered in any other 4x4. The lockers work!!!! A must have!!!! Remember ESP is for ice and slick roads. Turn it off if you are off, the road that is!!!!

 

Locker and a winch are really necessities if you'll be going offroad a lot. The lockers can really make a gard spot easy and a harder spot easier. I'll not own a Jeep without lockers.

 

My factory rubi lockers work just fine in 4 HI and 2 wheel drive

 

For what it is worth...

The factory ESP switch does not fully shut off all the traction control mumbo jumbo... even if you hold it for 5 seconds and listen for the beep. You can prove it to yourself by trying to whip a shitty in 2 wheel.

When switching into 4lo the ESP system automatically shuts off.

 

After the mod, of course.

It should come that way from the factory!

 

If you are already planning on doing a re-gear I would suggest finding a D44 Rubicon with the gear ratio that you are wanting. While most Rubicons came with 4.10 gearing (lockers standard) it is possible to find other ratios from people upgrading to either D60 or ProRock D44's. They can be found on this and other forums. The advantage of doing this is you not only get lockers, the gearing that you want, but you also have a stronger axle/gear assembly for a cost not much different than doing a regear. You most likely have a D30 in the front and a D44 in the rear with gearing to optimize the highway MPG for better marketing rather than gearing for off roading. Having a non-Rubi JK come with 3.73 or 3.21 gears is common. Rubicon front D44 is, in my (not so) humble opinion, a better choice and I would also recommend a Rubicon D44 for the rear as well since the regular D44 rear has a 30 spline and a Rubicon D44 rear has a 32 spline. The D30 has 27 splines and the Rubicon D44 front has 30 splines. In addition, the Ring and pinion of the D44 is considerably stronger in the D44 than in the D30.

My $.02 (and worth every penny you paid for it)

KG6SLC aka Eugene

 

Great advice at twice the price!

Seriously - good advice and a great upgrade path.