It's clear from looking over my pens that I'm a fan of TWSBI. The swipe is the latest in a great line of pens that I use on a day-in and day-out basis.
The first pen I've ever tried from Twsbi that used a converter, with the spring mechanism for that added bit of safety when the pen is bouncing around the bottom of my backpack.
The converter option also gives you the ability to flush cleaning water through the pen more easily than the regular piston fill mechanisms. If you like to rotate your inks regularly this is a big win.
Pair this up with a favourite ink (like WonderPens Writing Desk)!