Once the video is transferred from the micro-SD, it's not going anywhere and it's not taking up space on the one card that lives with my
P4P. I know you realize that; I'm just saying that there is not a single method which is optimal for everyone. 98% of my flights take off and land within a short walk of my house, so even if I'm flying two batteries worth, I can step inside and download the footage from the first flight, put the card back in the bird and go fly the second battery.
Speaking of YouTube, it does amaze me how small the files are without being total junk. I've got around 300 quad copter videos uploaded to YouTube. For some of those, I've given thought to downloading the small file from YouTube and deleting the original files, which are anywhere from 20 to 100 times the size. I should do that... it's not like there will ever be some great need for the original files that are taking up so much space.