Well, I've had an evening to play with it, and I am 200% happy I made the decision to drop the centibuck and get it.
First, it flies really well. I was surprised to find it actually has Visual Positioning -- there's a fixed, low-res (0.3mp) downward-pointing camera that you can take snaps with. Parrot lists the camera as providing "horizontal positioning" in the specs. Go figure. And I paid a grand to get this sort of sophistication in the P4

I've seen behavior that clearly shows a much less sophisticated algorithm for VP, and it's doing it with a single, much lower resolution camera, so it's clearly not anywhere near as good a system. You can easily fool it by moving something around under the drone while it's hovering (like your hand) -- it's isn't smart enough to understand that there's something below it moving, not IT moving over the static fixed surface its hovering over. The P4 doesn't make this mistake. Can snap pics with the camera that are stored on the drone and can then be downloaded.
Also has an ultrasonic ranging sensor pointing down for vertical positioning, as well as a barometer for elevations above 13 feet. Also a full six-axis IMU with accelerometers and gyros, used as a "contact" sensor (really just sensing an impulse acceleration) in addition to orientation/speed control.
Anyway, flies great! Not nearly as stable as the P4, but that's expected. Great practice flyer, and totally flyable indoors.
Does some neat pre-programmed tricks -- will flip in any of the 4 directions with the push of a button. Also, can launch by tossing it by hand, which is fun.
CONS: No traditional controller, operated from a smart device (phone or tablet, iOS or Android). A traditional 2-stick controller is available, the Parrot Flypad, but that's another $50 or so. Ordered one. Flying classic stick mode is very difficult without any tactile feedback. It's just really difficult to keep your eyes on the drone, and have any idea where your thumbs are on the virtual sticks on the flat, smooth screen. Stick mode is, therefore, pretty unusable. There is a gyro mode, however, that controls pitch and roll via the smart device's accelerometers (if equipped -- virtually every smart phone/tablet these days have IMU), so the right stick can be eliminated and controlled by tilting the phone/tablet, while keep your eyes on the drone. This works pretty well. Still have to use the "stick" for yaw and thrust.
Other con is the system uses bluetooth for communication instead of wifi or some other radio technology. This hasn't proven to be an issue yet, as it works just fine indoors, no lost signal, no delays in response or anything. However, the range is limited to about 20-30m, so this ain't a major traveler like the Phantoms. Doesn't matter -- there's no through-camera viewing, so its only LOS flying, and the thing is small enough that at 60 feet I expect it's getting hard to see it well enough to really use it in any meaningful way.
I would highly recommend this drone, or any of it's comparable competitors, for Phantom owners. I'm beginning to think that, at the price of the P4, they should just throw one of these in with the package. If no one's put together a bundle like this they should. Good for practice, good for satisfying that NEED when the weather's bad
