I had great luck with my ARBs. Never had a problem at all and drove that truck all over the country to 4Wheel meets.
When you say high speed, are you talking about road racing or turning them on or off at high speeds? Is driving really fast overheating the O-Rings? Or are you talking about the weird steering behavior with the locker on driving at high speed???
G
Let me start by saying that everything breaks, and personally I've seen one ARB and three Detroits have catastrophic failures. The ARB's center pinion support broke (we think) and munched everything inside. All three Detroits were the victim of backlash from axle breakage.
The non-catastrophic ARB failures I've seen are primarily in severe use (rock crawling, high speed sand or mud) scenarios. Usually they are not a result of the unit itself failing, but air lines, gummed up solenoid valves or flaky compressors. Some times it's bad planning on the installation. I've helped replace more O rings at camp than I care to think about, but I don't have any data on WHY they fail. Nonetheless it always seems like we have a guy with an ARB acting up. It's a shame for the cost involved.
ARB recommends against engaging the locker under drive line torque, which means in the OPs case, he'd really want to run the locker engaged from the start line. I'm not sure if he wants a 100% spool at speed on pavement. Mechanicals lock under drive line torque and unlock when that torque is removed. To me, that's just a simpler system. Especially for purposely breaking traction. My 85 drifts on dirt and gravel roads. :top:
Now, ARBs are huge with the overland crowd and if I were to lock the front of my Taco, it would probably be with an ARB. But in my crawler where I need it to work and take a LOT of abuse? Detroit. IMO the OPs case is an abuse scenario, not a traction scenario.