Earlier quoted context omitted.
In my view, Lamy Safari is way overrated. Don't get me wrong, it's far from bad, a pretty consistent pen for the price. But the ink dries fast-ish if you don't use it, and especially, the cartridges are proprietary so you're tied to the brand's cartridges and ink colors (there's a piston converter, but converters, meh). A Pilot Metropolitan is approximately the same price and at least in my view, it's better as it us…
Can you also use cartridges with the TWSBI Eco? A first pen should give you the option. I haven't tried the Pilots, but the standard cartridge could change my recommendation to them.
The TWSBI Swipe supports both cartridges and converters.