What if there is no smooth surface around?
95% of ordinary tables f.i. won't work with this. DON'T forget that. :-)
One big problem over here (Belgium, Europe) with any drone, though: virtually impossible to fly legally. I've been thinking about bying one, but I've buried the idea. Rules and fees make it impossible. If you think in investing money in these companies: think again. It will become the same everywhere.