Both are workable.
In General, a wired (Ethernet) is always best choice because a direct connection does not suffer from any interference that Wi-Fi connections are subjected to.
The speed of a direct cable connection is always faster than a Wi-Fi connection.
If your broadband router in the same room as your TV then you can connect directly to your device via a cable.
If your Broadband router is in another room or even another floor then you can use Wi-Fi or our Home network kits which will give you a wired connection.