The X10 guys practically invented spam. ;-) They definately invented the pop-up web ad. And then the pop-under ad.

I've seen some of their stuff -- it ranges from low to moderate quality, with appropriate prices. The X10 powerline protocol is cheesy in the extreme -- it can work well inside a house, but once you're dealing with the X10 transmitter being on one side of the centertap of your 240V pole peg, and the receiver is on the other side, most bets are off -- so you start needing to duplicate your X10 controllers on both sides of the center tap.

I have no experience with any of their wireless stuff that wasn't part of a X10 system.