i have very limited experience, but differential locks, especially those electronic, only adding complexity and possible failure point. traction control as is in latest defender works awesome well (lookup videos on youtube where they compare it to toyola), is very simple to implement and do reliable and even me (read: not an experienced offroader) was able to go outside of specs with that car and used central diff lock just once which was actually case where i had traction only on one wheel (bottomed on tree).
i believe that once defender will be available in US and other countries easier, the sell ration will break again favoring land rovers. they will be also able to go down with price and market it more when not manufactured at loss

 

I was recently offroading and saw a lifted jeep get stuck on a trail my rover could easilly make it up. The trail was in a small dirt cannon with alternating ditches on left and right sides. The ditches were deep enough that the wheels would not touch down. The jeep had open differentials. As the jeep drove up it got stuck with the front right and rear left wheel in te air. If it had lockers it could have driven out without any trouble.

The real danger with lockers is in making a sharp turn on terrain where you have good traction. When turning sharply the inside wheels turn slower then the outside ones. This reasults in a broken axle.

Optimally limited slip differentials or torque biased differential lockers would be used. Both styles are completely mechanical and reliable.

Regarding the traction control on rovers. I haven't heard of them being unreliable.

 

few days ago we were driving on a beach where hilux with deflated desert eagle tires got stuck in deep dry sand. we were not only able to go through (sand was up to our differentials, we left tires at 40PSI because didnt had compressor with us), half wheels in the sand all the times, but we also successfully gave him tow to wet part of the beach where he got traction again. i was so amazed because i couldnt believe it was actually able to go. our defender is lowered and was loaded with 4 person.