the twist type converters are always better than the push and pull ones as they have bigger reservoir than those pull-push ones, also they are protected against accidental spills by accidental pushes, but technology itself doesn't guarantee the best if things don't work as intended, the one I received was a leaky one, on close observation I found that the rubber piston of the converter leaves a significant gap between the walls of the converter and itself for the ink to leak in the barrel from the back side of the converter, when the pen is stored in the pocket. Anyway I wasn't in to for getting in the headache of a replacement or a return for a simple converter so I decided to live with it (& would eventually throw it away once the problem gets any worse), but this really isn't the quality that many would be expecting from an international brand like LAMY.