Make sure it's a 3G version Jaba. If you desperately need data, use it on your WIFI or get a pre-paid. You'll probably find that you don't need data very often if you already have an iPhone.
I've already offered my feedback privately, but in the public in case others can improve on it, I was after the ability to measure on the screen by drawing a line like you can on a 430 / 296 etc. If I'm going to fly past a CTAF I want to know how close I am going to be to it, so in essence a "multi goto" feature where the primary waypoint stays in memory, however an additional distance appears next to the line that I have just drawn.
Maybe a scale at the bottom of the map would be good too and custom waypoints - but keeping in mind that usually in TSO'ed GPS's such as airline jobbies, they often don't allow you to enter custom waypoints so that you don't screw up.
Great work gents,
