Ours were probably getting hammered pretty hard for recreational users. We did 1-3 rides almost every weekend for about 4.5 years. Every ride would involve filling at least four and rarely as many as 12 tires from 9psi up to 35 psi in hot, dusty, sandy conditions. My wife and I each had an ARB twin, and both had to be rebuilt. We tried to protect them by mounting them inside the cabin so they were breathing filtered, air-conditioned air instead of hot gritty air in the engine compartment. No problems with the motors, but over time, the ARB's would just not push as much air.
Both also blew the maxi fuses once, but never repeated that problem. The twin unit has two Maxi fuses. One (fuse-A) is in the circuit that controls the unit overall and powers one of the motors, the other (fuse-B) is in a circuit that just powers the second motor. So you can blow fuse A and the unit will keep running, but just fill slower. If you blow fuse-B, you lose everything, but can switch fuses and get back in business. When my wife's blew a fuse it stopped the compressor, and we didn't know enough about it to swap fuses. When mine blew a fuse, it just stopped one side, and the compressor kept going, it just produced less air. I only noticed it because it was taking so long to fill the tire.
We had several friends that had hardmounted and portable versions of the ARB twin compressor. Many of them also had them rebuilt at some point.
Club members probably five times as many of the Bushranger (Viaire?) compressors being run in the same conditions. The only problem I know of is that mine cut out due to heat once and I had to wait for it to cool down. That was on tire number 6 in about 125 deg heat. I can forgive it.
Bottom line, they are both good compressors, and most users probably would not see the problems we did on the ARB's. But under hard use, the ARB's lost performance where the Bushrangers kept on chugging. The ARB twin has some built in redundancy that is somewhat appealing, but the Bushranger never needed it.