LFS gives me an Environment where I have the possibility to grow with an almost unlimited amount. The whole package gives something our mind can learn, get better. All of that with a reasonable good real-life simulation.
Then the whole community, the possibility of some added development (lapper and so on) to tweak it for another communities taste makes the LFS package something unique.
Never has it been so easy to just say 'LETS START A NICE LEAGUE' where it's just very easy to jump in and start growing and getting better.
No other sim has that I think, and that's unique about LFS.
Now I didn't talk about physics and graphics at all