ARB locker airlines are not high pressure and are easily repaired. Google, “ARB air line repair kit”. For those especially worried about line failure ARB also makes line in braided stainless steel.This is a good point, but may not be true depending on the person, geographic location, or wheeling expectations. It also may be a cost or budget issue. It is hard for some to justify a $200-300 air compressor on a $5-10k vehicle without installing lockers. Anyone installing a locker would benefit from having the onboard air system, but they should already have been carrying an air source before wheeling at all.
There are a lot of people who use a portable air compressor in place of the on-board units. I typically carry my M12 air compressor (rated up to 120psi) for air duty since it was cheaper and can be moved between my vehicles. Before that I used the compressor built into the Stanley jumpboxes that I keep in each vehicle. These also have the benefit of not needing to find a permanent mounting point in the vehicle. I can even carry it to a vehicle on the trail without needing to park next to it or get a long hose.
ARB has a proven design, and I do not believe their large components (locker or pump) would fail. However, if something damages a high pressure air line, I am not sure of an easy trail fix besides carrying spare line. The ARB locker engages at 70psi and they recommend supplying 100-150psi. A cut or tear to this line, although unlikely, could happen. This cannot be fixed with duct tape or even rescue tape to get it to engage again. The damaged section has to be cut out and replaced with new line and couplers, which is exactly what ARB sells as their trail service kit. At least the OEM low pressure system is 4psi which I can get to hold with enough gorilla tape or spare vacuum hose (usually rated to ~10psi) until I get off the trail. The E-locker would just need the wires reconnected to a 12V power source or spliced back together, which could be done with pliers and butt splices (as long as a smart installer leaves a little excess in case of repairs). Tree branches jab at weird angles, rocks seem to sneak up on weak points, and a random sharp object could be anywhere.
I would also be interested in seeing the total price of each system installed on the same vehicle. E-lockers requiring 2 differential installs, switches and a 12V connection, and the ARB with on-board air. I think they may be closer in price since the E-lockers tend to cost a little more, depending on the installer charges. DIY install, I believe ARB is cheaper.
I considered both, but I will stick with the rear hybrid LSD and traction control. I have yet to get stuck or need to turn around, and the largest boulders I have had to cross were the ones near Rabun Bald Mt. If I leave the east coast, I would probably reconsider these options again.