Surprising to see that this article has snubbed Chinese FP manufacturers. I own over 20 FPs and some of my favorites are ones made by Jinhao and WingSung. One might even say that the WingSung 300x [1] is better made than the pens that it is a copy of, i.e., TWSBI's Eco and Diamond. The Eco's body is made out of cheap plastic that decomposes when it comes to contact with many household chemicals (e.g., isopropyl alcohol). The Diamond's body is ostensibly better made, but IMHO it's still not worth the price. In comparison, I've used a <$5 WingSung 300x for over 3 years now and it's one of the best pens I've used hands down.
[1]: https://www.ebay.com/sch/i.html?_nkw=wingsung+piston