SD Card.
I am in a country where we get a huge mix of great 4G LTE coverage in some areas to nothing but EDGE within the same area by just one move e.g. at my Father's place, where I get either 4G or EDGE and nothing else, while here at home I get H+ and EDGE, no 4G LTE. So with such sporadic speeds, I simply cannot rely on Cloud.
Yes, I do have WiFi at home, but its capped.
Got a Note 4 with 32GB Internal Memory plus 2 32GB MicroSD cards, I plan on getting a 64GB MicroSDXC soon though. Have a ton of photos, vids, series, music and docs. I back them up to both my work and home laptops. I use cloud for important work stuff like presentations, research etc..., so in case I lose my laptop or if I forget it, at least I can log on Google Drive and get the data.