Tethered chargers
The charging cable stays attached to the unit, so daily charging is quick and there is no separate cable to retrieve. Check cable length, storage and whether the connector suits your current and likely future vehicles.
Untethered chargers
The unit has a socket and you connect a removable cable. This can look neater when the charger is not in use and makes cable replacement straightforward, but you need to store and handle the cable.
Questions to include in a quote
Tell installers where the car parks relative to the wall, which side its charging port is on, whether the cable would cross a path and how important appearance is. These details are often more useful than choosing from a product list first.