I'll just make a prediction: If the UPB manufacturers get serious about continuously improving this technology to make it robust in all the conditions that their potential customers use it, then this will be a very successful technology that could finally bring home automation to the mainstream. If they don't, then they will all be out of business as soon as someone else does. And someone definitely will...
UPB manufactures are interested in improving the quality of their products, which is evident when they introduced the Gen II products. The new generation fixed most of the noise issues that affected the Gen I devices.
I might possibly try a HAI Gen II switch and PIM, to see if you have the same issues; although based on some of the previous posts, it does sound like you may have some other issue that might be creating severe noise, so I might look at that first. I think it was a good suggestion to try to take your laptop and PIM to a neighbor's house, to see if the noise levels are the same.
FWIW, I spent over a year reasearching HA before I got my feet wet, and had initially decided on ALC lighting. I even ran all of the wiring to every switch, when we built our house last year. I actually decided to forego ALC, instead opting for UPB, and have been very happy with the results. I currently have about 20 switches installed, and haven't had a single problem with them.