I've been running a Quad now for about 8 months. It's been great. It's the only thing I've got plugged into the Rail Pressure Sensor though. Even still, it's isolated because it doesn't draw current off of the RP sensor line. It pulls it's power directly from the fuse box and is only "piggy backed" into the RP sensor. Ain't no way it can get stray voltage unless there is a short of some kind!!
Many of the failures, I believe, can be traced to having more than one "appliance" plugged into the RP sensor and/or having those "appliances" draw power current from that line directly!!!