At the beginning, we had a happy marriage with this Furman Power Conditioner. However, as in many cases, things went south after almost a year living together.
A very audible hum started out of nothing, and was impossible to mitigate it. Being lazy to send the unit somewhere to get fixed, I opened it myself and realized that the hum mas caused by the light transformer. I just cut the cables and solver the problem in an Instant.
After that surgery, our marriage is again a happy one. However, if you are thinking about marrying one of these beauties, which I highly recommend, go for the Power Conditioner that has no lights. It will be cheaper, you won't have any problems like mine, and your marriage will last forever.