I have been using Faber-Castell artists pitt pens and I really like them!They have a very consistent, dark line. The set I bought comes with 4 nib sizes (see the image) below:
The ones I end up using the most are the S/B sizes (S for fine work and B for more broad strokes). By the way the B size gives some really cool effects. I don't really use that much the other sizes but still is good to have them, just in case I need to fill up some large areas.
Here is a drawing I made with them in combination with a white color pencil:
Overall these preform really well and I didn't find them that expensive.