just one thing to think about: the ALTA is the only multirotor i know with such a detailed manual. It is all about the conditions you want to fly in. i had two selfmade cinestar 8 with wkm and was able to fly my FS100 for about 8-9 minutes with one 10A 5s batterie. the first time when i flew one of that machines in the alps for "terra x", i landed after 4 minutes and the my batterie was 3,5V/cell... there are thousands of drones out there flying way over their real payload maximum but their owners don't know. An ALTA sure can fly an epic or a mini. maybe not in the alps at 30° Celsius. And may you have to figure out how to get the payload limit (using lighter batteries with high C-rate) but IF you do that you are safe.