I am up to my third pair of commtrends not because they were faulty but because it's far easier and effective than wifi around the house; faster speeds, consistent connectivity plus they actually leave wi-fi available for when its needed rather than choking the bandwidth with many items connected to it.
An added advantage for xbox 360 users is that the lan speed is much faster than over wifi for gaming and watching videos/media center - plus you dont need the expensive xbox wireless adapter!
Admittedly getting onto my second pair of adapters was a problem due to a lack of manual but Google provided me with how to setup additional units and I have founded the latest version (in black) to have a far more complicated manual, but the process from the original bulkier units (in white) still applies.
Basically each pair of adapters is 'paired' to each other so they only talk within their own point to point network; adding another pair (to add more devices to the network) requires you to reformat the new devices and sync them to your existing network adapters.
This is done by locating the master network adapter (i.e. the one that your router/bt homehub leads to and then out through mains electricity to your other adapters) and performing the following (note its easier to put the master and the new adapter into a double wall socket together to save you running from point to point - dont worry about unplugging the device as it retains settings.)
1. On the new device perform a factory reboot by powering it up from the wall and holding the config/reset buttong for 15 seconds - the unit will now turn off and on.
2. On the master device hold the config/reset button for 4 seconds until the AP light flashes red (let go or it will eventually perfrm a factory reboot.)
3. On the new device hold the config/reset button for 4 seconds until that flashes
4. The new device will now share the security settings of the existing network
Being a BT Home hub customer I can tell you that the network doesnt work from device to device like it may sound; i.e. from 1 adapter to the other pair - you only need the bt home hub/router to have 1 connected adapter and then you can add lots of adapters around the house; so buying 2 pairs (2 masters and 2 slaves) means you can reformat one of the masters to give you 3 network points and from then on every new pair you buy is another 2 access points.
In terms of range I have the router downstairs and a number of pcs and xboxes throughout the house, I also have an external office in a garage conversion with an RCD connected from the house and the signal travels over to my electric points so a great solution when wifi drops off outside of the house and in the garden.
Definately a great product but the latest manual is very offputting and technical requiring you to hook computers up to the adapter, so use the above method and you should be fine.