The application is home use in a terrace house, so all power outlets are close in a small house, but perhaps there is a possibility of interference from neighbouring units?
Since it's plugging into mains power, electrical safety and reliability are key factors. I've seen some people using the Netcomm NP204 - are these good, or are there better options these days?
The AC passthrough on some models looks like a good feature, as some people have suggested that these powerline devices should always be plugged direct to the wall socket and not into a multiboard as some multiboard will filter out the high frequencies.
In an ideal world, I'd like to run cat 5e / cat 6 everywhere. However, concrete construction makes for a non-leaky terrace house, but difficult to add wiring.
There might be a need to connect multiple rooms too, if that makes a difference.