I saw a review that mentioned the lose valve core issue. Ironically, the same day I was testing out some new tires, and was going to lower the pressure. I unscrewed only the plastic valve stem cover and accidentally removed the core, and lost all my air. I will be tightening all my cores now and carrying a tool with me. I don't think the screw on hose of a pump will be an issue and I like the idea of a screw down attachment rather than a press and clamp type.
The Stompump like allot of the Lezyne and several others does have the screw on presta chuck. I like the Jaco better and once I have the Stompump and know the thread pitch on there chuck, I will see if the Jaco will work.