Otherwise I’d recommend a modern Pelikan M200 (or similar but more expensive, like an M400).
Unless you are looking for a pen that takes cartridges. For a cartridge pen, I don’t know, although the Levenger True Writer is a good one for the price (especially since I got mine for $15, but that was for a discontinued color). Not the best construction, though—mine has a loose cap band. Writes very nicely, nevertheless, at least with some inks and papers, I don’t remember which, and I’m not sure if I ever used a cartridge in it instead of a converter.
BTW in gold nibs, 14-karat is generally preferable over 18-karat. I think 18-karat gold gets around laws in some places, basically letting you call it gold, so it’s the popularity of 18-karat gold with modern manufacturers is a sort of concession to pens being also a sort of jewelry, but 18-karat gold is harder to make a good nib from. (Though I actually have a 22-karat nib in one pen, which has a very soft feel when pressed to the paper; it’s not too bad.)
