The 115, after approximately 150 hours of use, suffered a fairly catastrophic failure. A capacitor, or perhaps a resistor (it has been a while since high school physics), became overheated and flamed out rather dramatically. I returned the unit to ARC, via my local dealer.
It took quite a while, several weeks, for ARC to ultimately resolve the issue to my satisfaction. They sent me a new unit, which had the suspect part (and its boardmates) mounted much higher off the board, thereby hopefully solving the overheating problem. I've only run the new unit for a few hours, without any problems.
At no point did anyone indicate that the problem might have been related to the Ref 3 or any other components. I also have a CD-7 so obviously I am a fan of ARC products. As for the VS 115 I hope to get many years of good performance though I am inclined to look at a REF 110/210 or something else should any other problems occur.
My local dealer was very helpful and understanding throughout the process.