The single biggest thing for me is the unified system design and implementation.
That is, it's not like Linux/BSD desktop environments where the kernel, display server, window manager, desktop shell, file manager, distribution ... are all developed by separate teams in separate code repositories with separate goals, schedules, standards, etc. In Haiku, you can change the UI toolkit, display server, and init system all in a single commit to one repository.
This has a massive array of advantages. It means we never go back and forth about where responsibility for a bug lies, only where it should be fixed. It means we can decide to go with or against trends and standards as it makes sense to (our package manager is probably the biggest example of this.)
Virtually everything else I like about Haiku stems from this, whether it's the timeless UI, the overall system architecture, or even the code itself (which is a genuine pleasure to just read, not something that one can often say about any project.)
That is, it's not like Linux/BSD desktop environments where the kernel, display server, window manager, desktop shell, file manager, distribution ... are all developed by separate teams in separate code repositories with separate goals, schedules, standards, etc. In Haiku, you can change the UI toolkit, display server, and init system all in a single commit to one repository.
This has a massive array of advantages. It means we never go back and forth about where responsibility for a bug lies, only where it should be fixed. It means we can decide to go with or against trends and standards as it makes sense to (our package manager is probably the biggest example of this.)
Virtually everything else I like about Haiku stems from this, whether it's the timeless UI, the overall system architecture, or even the code itself (which is a genuine pleasure to just read, not something that one can often say about any project.)