Columbus Circle will soon be releasing a new LAN Adapter for the Switch in just a matter of weeks. It will be launching on Amazon Japan on May 31, 2019 for the price of 2,570 yen ($22.98 USD). This is a little less than the officially licensed LAN Adapter made by HORI which goes for $29.99.
In fact, there are a lot of other cheaper options on Amazon US that show compatibility with the Switch, such as one made by UGreen which is only $11.95. The key difference is that unlike this new one from Columbus Circle is that a lot of cheaper adapters are USB 2.0 rather than USB 3.0 compatible. USB 3.0 can handle more data, so it is technically better. Still, unless Columbus Circle releases its LAN Adapter officially in the West, it might be easier to go with the cheaper options anyway.
The Switch’s Wi-Fi capabilities are okay, though some users have reported it having a weak signal despite other devices not showing similar results. That’s also true for my own unit. On top of that, having a wired Ethernet connection is always superior to Wi-Fi regardless. The only real downside is that (aside from having an extra cable attached to the dock), the functionality can only be used when the Switch is connected to a TV. Even so, having a LAN Adapter is nice if you do play online a lot and/or download digital titles often.