Has anyone played Dwarf Fortress? It caught my attention recently but I do not dare to touch for many reasons, like the graphics (people say they tire your vision), the complexity and hardness. I like challenges, but not intense ones...

In the other hand, I bought Rimworld, which is like an enhanced version of DF but I guess it has a lot less features since DF is not even done yet and still growing I heard. So far I am in love with this game.

Just some questions, how complex, fun and hard is DF? I heard it leaves amazing and long stories while your game and world evolves. Still, I don't think I will touch it.  

I liked DF, though it is complex and nearly impossible to get into without help from the wiki.
At first I didn't want to play it with the asci gfx because I was worried it would be bad for my eyes, but I ended up playing without skins eventually because some update or other made them not work anymore. iirc it wasn't so bad once I learned what symbol represented what, though I'd still recommend useing a gfx pack or whatever it is called when you start, before you've learned the game.
There are a lot of tools that makes the game easier to manage too.