Re: ballistics computing choice!
P.S. - that phone is not your only option. There are several ruggedized PDA platforms in that price range, like the TDS Recon, for field ballistic programs. I don't like phones in that application. Phones are active emitters, and frequently battery hogs as well.
Or you could just go with a more conventional PDA in an Otter Box if you don't need a full ruggedized solution in your application, or build a density altitude ballistics table and do without the PDA at all.