Takeaways and Where to Buy
I always recommend TWSBI pens to people who are interested in trying a piston-filler fountain pen for the first time. The barrier to entry is lower than a Pelikan M200 or a Lamy 2000, and TWSBI generally offers a relatively inexpensive, reliable writing experience while still allowing people to dabble in the "limited edition" craze. For the past few years, TWSBI has released a series of AL (aluminum) trim models in various colors. If you like the AL Gold model pictured in this review, I'd jump on that pretty fast because they seem to be getting scarce, and TWSBI will likely replace them with a new color sometime this year. The standard Diamond Mini, however, is pretty much always available, and also comes in a black "classic" configuration. I typically order all of my TWSBI's through Amazon.
Note: The reputation of TWSBI's "Diamond" models (the 580 and the Diamond Mini) have suffered a bit in years past due to reports of barrels cracking. More recently, TWSBI seems to have improved both their quality control and manufacturing process. I've personally never suffered any sort of catastrophic failure or ink leakage, even on one Diamond Mini that developed hairline cracks on the section. (This was an initial run model from four or five years ago.) Regardless, TWSBI is known for having good customer service, so if you run into a problem, they will make it right.
Disclaimer: I purchased the pen featured in this review with my own funds, for my own use. This post does contain affiliate links. Pricing and availability is current as of the time of this review.