To answer this I’ll start with what I don’t like.

• Scratchy nibs
  
• A very thin line

In the past I have been more into medium and broad nibs. These days I prefer a stub or anything that makes my wrting be varied and look more interesting. But I have also noticed that my writing works better with finer nibs. So where I’m in the past was a borad and medium guy, I’ll probably do more fine and medium in the future.

To be honest I think everyone start out with “I like this type of nib” and then at some point they move away from that and instead focus on what attributes they like or dislike.