I have a VooDoo labs ISO-5 power supply, it is WONDERFUL. Professional quality, short-circuit protected, and dead quiet on my pedalboard. VooDoo labs' power supplies are the ones to get if you can afford them.
Your post, by the way, seems typical of many from 1spot users. It works great for most people until they add another pedal to their board, and then they suddenly notice weird noises. It seems the 1spot's switching power supply is more prone to generating noise when it's got a higher load on it, which makes sense if you know how switching power supplies work.
"I have no actual information, just what the salesman told me."