It seems pretty accurate from the bit that I have used it. You're obviously correct on the DA issue as well. Guess the only way is to use it for a while and compare.
edit:
How do I assure AE is using the input? If I select the little blue "update environmentals" icon in the top right corner (looks like an inverted teardrop) how do i know its not grabbing sy an NOAA site miles away? Howdoitknow?[/QUOTE l]
Set your phone the "Airplane Mode"; that should disable your data link; then try using AE. Alternately, call a buddy/wife/gf who will lwave the line open while you fiddle with AE. Either method suould temporarily disable your data link and allow you to figger out where the info is coming from.
Edit: I just tried this with AE, and it was a fail. AE queries NOAA weather stations based on your phone's location, and with my iPhone in Airplane Mode, I got a "query failed" error message. As to the accuracy of these sensors, they are actually pretty good; they are in Kestrels, Sig 2400 and other rangefinders with built-in ballistics engines. They are also inexpensive, so incorporation into electronics is "merely" a question of board space and code. I'm going to compare the iPhone readings with my Kestrel 5200 Elite and Sig 2400; we'll see how they all match up.
Edit again: tested AB and Trasol in airplane mode: AB seems to pull Station Pressure from the onboard sensor, and I know SIG does. Trasol seems to require a data connection and location.