Ubiquiti is most commonly known for their UniFi access points. UniFi is much more of a diverse home/office networking system . It’s an ecosystem with different models of wireless access points, routers, switches, security cameras, controller appliances, VoIP phones, and access control products. Some of their newer devices like the UniFi Dream Machine (UDM) and UniFi Dream Machine Pro (UDM-Pro), combine a number of functions.
AmpliFi is mesh Wi-Fi on easy mode. AmpliFi devices are meant to be quick and easy to setup, while giving you broader Wi-Fi coverage than a single all-in-one router or a single access point will give you. If you just want to plug it in and have it work, AmpliFi is for you. There are no VLANs or complicated firewall rules to worry about. You get one single network, and an optional guest network. Amplifi HD comes stand-alone or as a Mesh Kit.
The AmpliFi Instant is as simple stuff. They come in one or two packs. Buy as many of them as you need. They typically come in a 3-pack, featuring one base station and 2 mesh nodes.
AmpliFi devices don’t use the UniFi controller, web interface, or the UniFi mobile applications. They have their own mobile application, and that’s the only method you have to configure or monitor them. Initial setup can be done in a web browser, but most controls are in the mobile app.
UniFi hardware is a nice middle ground network offering. With more features than most consumer-grade brands, but lacking the expense and complexity of enterprise.