I mainly ride track and also often run twin discs so this is something that gets alot of use.
I'll get the major downside out of the way now - EVERYONE in the pits at the track wants to use my pump now...
Probably says volumes for how well it compares to any other high pressure track pumps with a disc chuck on!
Hiro chuck is faultless and the entire pump is a pleasure to use - if pumping tyres is a daily interaction for you and you enjoy the tactility of using quality mechanical things then just get this thing, years of pleasure using something this well made ahead of you. Mine gets a ridiculous amount of use and I'm confident it will last years, the build quality is something you cannot fully appreciate unless you have it to hand.