I'm not sure on the new ones but my 2002 3500 dually dmax/allison had the Eaton G80 locking rear axle. Probably one of the best from the factory locking rears. Not limited slip. My new truck has the electronic locking rear F350 SRW but have not really had a need to use it yet.
2011 F350 KR 4X4 CC LB SRW
2012 Northern Lite 10 2 CDSE
2008 Custom Weld 17' Boat
2010 Can-Am 650XT Outlander Max
2012 Harley Tri Glide
I believe the famous Mr. Whazoo has a front Eaton E Locker on his GMC 2500. You could pm him for a review. The factory GM Eaton G80 rear locker is an excellent and I think by far the best of the big three rear axles.
Yes the G80 is available/standard on the dually. It was standard on the LTZ package on my 2500. Great truck by the way, you will/would love it.
2012 Chevy 2500HD LTZ CCSB 4x4 gas
2012 Four Wheel Camper Hawk
2008 Harley Street Glide
If you want an F350 dually with a locker, order the truck with the standard open rear differential, then have an aftermarket locker installed in it, either a Detroit Locker, or a Powertrax Lock-Right.
The GM 3500 dually does have the G80 locker available as a factory option, as far as I know.
I don't think I'd have a need for a locker in the front axle of a dually. The truck is too big to do any rock crawling or other really extreme off roading. A limited slip would be nice though. I'd look at the True Trac non-clutch limited slip for the front axle.
My '05 Dually has the G80 rear locker. It works great. There are several models of limited slip and locker available for the GM IFS axle. I don't think I'd want a locker in the front. Maybe an air or electric locker.
I am a fan of ARB... In my world we live and die by front/rear lockers and my money its ARB and I have seen a LOT of broken lockers. ARB plays RUFF! I have run them for many years f/r.
I Jeep. Hard core, axle snapping, spring twisting offroad jeeping. I've had Detroit, LockRight, Eaton E Locker, and ARB.
Detroit and LockRight - I found the lock/unlock hit and miss. They are mechanical lockers, and lock when they feel they need to, not you.
Eaton E Locker - I've found that it doesn't engage as instantly as an ARB. It also tends to stay locked for quite a while after unlocking it, making my Jeep hard to steer until it decides to finally unlock.
ARB - locks when you want instantly, unlocks nearly just as fast, and doesn't stay "hung" like the Eaton E-Locker does.
My vote for a locker in any rig is ARB. Bulletproof, works when it should, releases when it should.