I'll second (or 3rd, or 4th...?) a thumbs up on the Lezyne Road Drive. I haven't had any problems with it unscrewing the cores. If you have the space for it, get the largest one- I've got the medium, and it's fine, but the extra volume of the large would make pumping up easier. Also a shout-out to the Lezyne Mini Floor drive which I've got on my touring bike- slightly fussier to use (getting the head screwed on and off the base of the pump...), not as sleek as the Road Drive, but you can get it with a built in pressure gauge and being able to leverage against the ground/hold it with your foot makes pumping up pretty easy. And it has a reversible presta/schrader head.