I sold an English Parker Duofold the other day. What’s so special about that? Well, the Aerometric and AF Duofolds just don’t sell that well. It’s a strange thing. An English Duofold, in terms of quality, is as good a pen as the best of the 50s Swans, and that’s real quality. They don’t have any special problems. The sacs in the aerometric ones seem to last forever and the AFs are very straightforward to repair should they need a new sac. Some say they have a tendency to crack in the cap lip but I have handled lots of them and I can’t see that it’s a common problem.
They are perhaps a little bland to some eyes, but you could say the same thing about many self coloured modern pens which sell well enough. The nibs are generally inflexible but again, most modern pens are the same. The AF, in particular, has some nice features like the aluminium pushbutton and the better section. The plastic that they are made from, which I understand to be a form of Perspex, readily takes a beautiful shine with just a rub of a polishing cloth
When new, these were quite expensive pens, associated mostly with doctors, lawyers and other professionals. Now they go for buttons. It’s a strange old pen world.