No arguments from me. How well X10 works has a lot to do with where you live and what else is on the electrical system. X10 is not recommended for apartments as the electrical system is typically shared and may not be bridged (able to communicate) with all the rooms (or even to the outlet on the other side of the room
)
If you have high voltage drawing appliances, such as a window unit AC or full size freezer on the same circuit you will have problems.
If the wiring in the house is old you might have problems.
Sometimes getting X10 to work will require putting a filter on your electrical junction box to keep stray signals out. Did you know if one of your neighbors is running X10 it can screw up your install? You may need to wire a bridge between various circuits in the home. And lastly, depending on the size of the home, you may need a signal amplifier. Back when X10 was the only automation option, if you wanted reliable results, you had to do these things. You can test your home with a simple X10 install kit (you can get a starter kit for about 25 bucks) If it works, great-you can automate on the cheap. Got problems? Return it and take a look at one of the alternative protocols.
And of course the hardware for X10 is like anything else, some brands are better than others. I've had good luck ordering from SmartHome.com. They are not the cheapest but the equipment works and they stand behind their products.
But as I said, if money is not an issue then go for the new technology, Insteon, UPB or Z-Wave. Its like foobar and winamp or zoomplayer and Theater Tek - each have their supporters and detractors. Research them and go for what feels right to you.