@requiemI made the mistake years ago to focus on inferno, without thinking about the use case. The inferno use case tends to be like a java replacement. You'd build software (embedded or user software) and distribute that in your network. The user software most often will run as a packaged distribution on a host OS, but the end user never really touches inferno - not the OS part, and also not the desktop environment.
The inferno you probably know, the one that's distributed with the desktop, is mostly meant for the developers of said applications, as well as the engineers that manage the environment.
A good example for that is acme-sac, which is basically inferno with everything that's needed to run acme. There's no desktop GUI and acme runs in fullscreen mode.
Plan 9 on the other hand, even though it's developed as a research OS, feels like it's designed for actual daily use by "normal" users. Like, you'd run applications on it. Nowadays I'd recommend going straight to 9front, as it's more modern and comes with good new software and better hardware support, as well as better security.
Plus, you should be able to run inferno on plan 9 systems as well, even though I never tested that.