Whilst powerline adaptors are cheaper and can be fit for purpose, they do have several disadvantages.

1. They only work if both ends are on the same circuit.
For most homes, this won’t be a problem, however, if your home has more than one circuit due to an extension or any other reason, then problems.

2. They can be impacted by electrical Interference.
This is pretty common, for some devices, the effect is temporary (tumble dryers, microwaves, etc.) but for others, the impact can be more consistent (fridges and freezers). The issue should be fairly easy to spot; as the Powerline units have an indicator light which will normally be either orange or red if the connection is suffering from interference.

3. They lose speed.
Almost a continuation of the point above. No matter how little load is on your circuit, its primary role is to provide electricity and you will always experience some loss of speed. How much of a problem this is will depend on how much speed you have to lose? For example, losing 100Mbps from 350Mbps isn’t a huge problem, however, losing 5Mbps from 7Mbps is a huge problem. In that situation, you may want to either look at increasing your speed (if that’s an option) or extending your internet with another method.

4. They work better alone.
Powerline kits can have multiple end units, the number will depend on the model, and in theory, this allows multiple connections from the router. However, in our experience the more units the less reliable the connections. They are perfect for connecting to a single point but not really suitable as a complete home network solution.

5. They are limited by socket locations.
Seems obvious I know, but these adapters don’t work as well on extension leads, so if you have a powerline feeding a TV on the end of a 20m extension lead or even a long line of daisy-chained extenders, you will almost certainly find it doesn’t work or doesn’t work as well. Even on short extension leads you may see a significant loss in speed.

6. Different brands don’t work together
This is based purely on experience, if for example you have a Divola Powerline set in your house and then you add a TP link set, everything will stop working. Sometimes you actually see the devices on their competitor’s app but ultimately the system will fail.

7. They have limited configuration options
The selling point of Powerline devices is that they are very simple to set up, meaning most people can simply buy them from Amazon, plug them in and they are good to go.
However, this is a double-edged sword, especially for the Powerline Wi-Fi extenders. In some areas, for example, a block of flats, there can be a lot of Wifi networks and certain frequencies can become crowded. Too many people on a similar frequency can cause signal problems and interference causing your Wi-Fi to be slow or unreliable. Normally by switching frequencies, this issue will be resolved, however many Powerline adapters do not have the option of switching frequencies, so you’re stuck with a poorly performing device.
Generally speaking, we tend to suggest Powerline to customers who are light users, who are looking for a bit of extra coverage for their Wi-Fi, so they can browse on a tablet. For those higher-demand users, we would look at other options such as Ethernet cables, Access Points, or Mesh systems.