I've had both the ARB Airlocker & the Eaton e locker. They are both good units & seem to hold up well. From a driver stand point they work the same push the button & your locled up. Push the button again & your back to an open diff.
I got rid of the truck with the e-locker after about 50,000, but I have had the ARB units in 3 trucks that have gone over 200,000 & had no problems.
The nice extra with the ARB is you'll have air onboard & that comes in pretty handy when it's time to air back up.
You need to drill a small hole in the differential with both units for either the wires or the air line. Careful routing of the wires or the airline will prevent any problems.