I'm interested in purchasing a DJI quadcopter, however before I do, i'm curious if the issues i've been reading about are widespread or really focused on a small population? It seems most issues i've come across pertain to the invalid battery issue, fly aways, and drifting. Most of these issues seem to be reported late last year, so i'm curious if the issues have been resolved in newer production models, or firmware updates. If DJI is still ironing out the kinks, and it's really a roll of the dice at this point, I'd rather hold off. Thanks!