so i gave it a try this weekend. the interface is nice. you can fly a grid or free. grid is the equivalent of survey but it doesn't have sidelap, camera settings or hatch angle. you can control grid size, altitude, speed, gimbal angle and overlap. free is you fly manually, and pix4d will automatically take a photo every x meters.
when you create a grid, its easy to resize, rotate or shrink/enlarge. after you upload the mission, preflight checks are run, but for solo, two preflight checks have to be resolved. the first is that you have to take off with the controller. pix4d capture won't auto take off (even though it says that it can). and the second is the gopro file number reference. you need to know the number in the filename of the last photo taken by the gopro. pix4d capture tags each image taken in its logs with the name of the photo. so if this isn't correct, your whole mission is useless (more than that shortly).
once pre flight checks pass, and you are in the air you hold start for 3 seconds and away she goes. moving solo around was as expected, gimbal angle worked, gopro shutter worked. the absence of sidelap was disturbingly obvious though. once the mission is over, pix4d capture will return home, land and disarm.
and here is where the disappointment kicks in. pix4d capture cannot retrieve the images from the gopro and because of that, won't upload the project to the cloud. and unlike dronedeploy which lets you upload to the cloud from the browser, with pix4d capture, you can only upload to the cloud from pix4d mapper. so if you don't have pix4d mapper, you can't do anything with your shiny new mission.
so does it work? yes and no. you absolutely have to make sure that the file number reference is correct. and you also have to have pix4d mapper to upload for cloud processing.
