The Parker is me of the shape at the handle by far the best, provides highest quality and has, thanks to good mine a great writing experience. The Lamy has a good writing experience, but rattles for my taste too much and the metal grooves feel uncomfortable in the long run to. The Faber-Castell is me personally too bulky, the mine is not as good as the other two and the shape of the gummed area feels unnatural for me in terms of form. For this he is however also a bit cheaper.
Therefore, for me the conclusion relatively clear:
1. Parker IM
2. Lamy 206
3. Faber-Castell Grip Plus