I prefer ebonite, celluloid, and acrylic pens. But ebonite, though liked, is often pretty ugly. I guess the only attractive ebonite pens to my eye are polished black, or coated. Urushi lacquer over ebonite is viewed a lux. For celluloid, the color of the Omas Arco Brown are viewed as the most beautiful. Other marble or tortoise patterns are highly regarded. Acrylic is also available with a marbled pattern. I find the color and pattern of the Edison Antique Marble or the Bexley Amber material very attractive. Marble red or amber or tortoise are often found on lux pens and I like them. A transparent window to show ink supply is a nice feature.
Few pens are offered in polycarbonate. It's tougher than the resins above. But only available in solid color or transparent tint. And it's more difficult to machine and polish.
I had an expensive Delrin (acetal) pen once. It was so slippery that my hand fatigued gripping it.
I do not like metal on the section or the cap. I also object to metal rings at the bottom of the plastic section. These are common but can trap ink when you immerse the pen to fill it and even after a wipe, comes off on your fingers.
I like big nibs. They may have little or no functional advantage. But they look lux and are expected on lux pens like the Sailor King of Pen, Montblanc 149, and Pelikan M1000.
Piston fillers are viewed as superior to cartridge converters, and I'm trying to rid myself of that bias because a good converter can be replaced for $10 in a minute and piston problems (which are frequent) are expensive to fix. Converters also have a functional advantage of permitting a quick check of ink level by viewing the converter. Although windows in some piston pens allow that too.
I think the classiest clips don't rely on the flex of the clip itself. Rather the clip is rigid, but extends from a springy hinge. Rollers at the bottom of the clip are lux.
I like steel nibs. But many people here think gold is better. I think gold is inferior to steel. Bock makes excellent steel and gold nibs for a very wide range of manufacturers.
Size of a pen relates to lux. Look at the lux pens with large nibs for an example of size. I'd say 6" long cappped, 0.6" body diameter, and 0.5" section diameter are right. Weight in the range of 25 to 30 grams.
I like even bigger pens, but only if they weigh less than 38 grams.
You should have a good nib tuner available, either in-house or on-call. He should check every pen before you ship it.
A mistake made by some pen manufacturers to require too many turns to uncap a threaded cap. 1 to 1.5 turns are right. Many, including me like push caps. I modify pens to this state by machining an O-ring groove. But that's risky, and I'd guess 1 to 1.5 turns of thread is the safe approach.
I dislike gaudy pens, odd proportions (like some Montblanc Writers Editions), and narrow pens. I do like polygon cross-sections, like Omas Paragon. But this is much more costly to machine than round.
Edited by Precise, 20 September 2018 - 05:02.