I understand that the 800 is a better nib than the 600 (but feel free to sound off if you don't agree).

I imagine that the difference would lie primarily in the material used, 18k vs. 14k (but, again, feel free to sound off if you feel differently).

Unlike the 600's, the 625 and 650 uses an 18k nib--does that change anything? Does the 625/650 nib perform as smoothly as the 800? Does the 800 write appreciatively better than the 625/650?

Cheers,

Will

PS: I ordered my 625 with a medium nib, but I may want an additional nib later. Does Pelikan sell 18k 600 series nibs (I don't mind if it's two-toned).

I've got a bunch of M600 and M800 nibs. Any difference is so moot as to be undetectable. The big difference is going from either of those to an M1000 - now that's a *huge* difference!

18k isn't necessarily better than 14k. All things being equal -- which they never are -- 14k is generally more springy than 18k. That makes 14k somewhat more desirable for the purposes of springiness. That doesn't necessarily make it better for other purposes. In any case, one has to consider more than the materials involved.

From the nibsmith's point of view, 14K is better than 18K.

We are inundated with 18K nibs because of jewelry laws in France and other countries that prohibit labeling an item as gold if it isn't 18K or richer. These laws were formulated centuries ago to prevent fraud, but they now serve to promote the idea that 18K must of necessity be better than 14K if you can't even call 14k "gold." This has spilled over to pens, and we get 18K nibs in order that they can be labeled as gold. Don't fall for it. Demand 14K in your pens!