I had trouble figuring out how to move points on the corners of my rectangle when building the area to fly. The magic is to touch the corner marker to make it big (selected) and then touch the bottom of the marker/pointer to move it. Still struggle with my fat fingers hitting just the right spot to drag the corners, and once in a while I accidentally delete a point instead of moving it. #notamacguy
Another issue we are seeing periodically is our drone (phantom 4 pro) will go to the start point of the route and just hover indefinitely. I have to press the home button on the transmitter to get it back and try again. One time out I had to try 4 times to get it to fly a route and wasted 1 of my 3 batteries messing around with this. Sometimes it seems to help if you double tap the home button (ipad) to bring up the thumbnails of open apps, and then swipe the fieldagent app up and away and restart it. Other times this doesn't seem to help at all. I've reported it a couple times, but haven't heard back on what's going on. I'm told that the dji flight controller can't hold the entire route at once, so it trickles up a few points, flies them, trickles up a few more, and once in a while something get's stuck in the logic is the best I can guess.
We are flying with a sentera camera, so flying with field agent is nice because it knows about our camera field of view, does the overlap properly, etc. Let's you pick altitude, flight speed, % overlap, etc. It does a reasonable job of estimating flight time. If your job takes more than one battery (flight) it manages this well ... the drone comes back when the battery is low and lands. Just swap batteries and continue the flight.
When it all goes well, field agent is pretty slick and makes surveying an area super easy ... I just have to fight with the app once in a while, maybe because I'm #notamacguy or maybe there is a glitch or two lurking in the app and I have bad luck stumbling on these things? I don't believe they have an android version (or didn't last spring when we got our system up and flying.)
I know some of the sentera guys and they are a great company and always working to improve things, so I'm not complaining, just relaying my personal experiences with the app.