Not that Topeak and Leyzne and the other suggestions aren't above average, they certainly are, but I've never found a pump, no matter how cheap, that didn't successfully inflate presta and schrader tubes.
Any pump small enough to take with you is gonna take some time (for a big mnt tire) and/or effort (for a high pressure road tire) to use, and the smaller it is, the more that's true.
If you use it on both types of valves, then a dual valve head (or smart head that adapts itself) is nice. Unless you use both valves often, any pump will do (they all can be switched to either mode)
Get whatever is convenient and affordable. Chances are you'll lose it before it breaks