Unraid seems to be targeting a rather niche market of people who are used to building PCs for running Windows and would like to have a home server and self host some apps (usually Plex and the 'arr stack if we're being honest). It does a good job of making all this accessible via a nice web UI with basic hypervisor and container management features. The app store they have for Docker containers is great for exposing new users to what's out there.
The problem I've found is that while it does a good job of offering a low barrier to entry, the ceiling is quite low as well. It seems to me that the type of user they're trying to attract is also the type who would want to learn more and tinker, at which point Unraid's limitations will start to chafe.
If you've used other Linux distros you'll find the lack of a package manager and other atypical features frustrating. Once you want to go beyond their app store for containers the web UI becomes limiting. There's no first-party docker compose support. The hypervisor UI is quite limited as well, lacking even the ability to create and manage snapshots. Of course you can manage all this from the command line, but at that point you may as well use another OS with a more performant and reliable filesystem.
There are also some bizarre security choices that they've seemed to have had difficulty moving past. The web UI is only accessible as root, for example.