Hey Pelikan afficionados, I'm contemplating buying a used Pelikan with a gold nib (EF) and wanted to get your thoughts on selecting a 140, 400NN, or M400.

My budget is in the $200-250 range which I think is realistic? This would be the most I've been spent on a pen ($150 being the prior max) but I think it would be worth it.

See, I like my M205 except it is a bit persnickety about ink and the nib behaves kind of oddly. I go back and forth on how I feel about it.

But I've tried M600, M800, M1000, and some flexy/bouncy vintage 100 (or maybe it was a140?) and found each truly superb, the latter in particular. I think I would rather spend the money to get one of these 3 higher end models and sell the M205.

Are the nibs of any of these models notably different to the others in any way? Like, flexibility, smoothness, flow, etc?

Any known issues with filling systems on any? Are DIY repairs reasonably easy? (I've refurbished Vacumatics and button/lever fillers and Parker 21s).

Anything else to watch out for on any of these?

Any clear advantages to one over the others?

Thanks in advance.