There is clear difference between two.
In case of Twitter/FB bounties, work is negligible. You can do 30-35 bounties at the same time devoting an hour or one and a half daily. But disadvantage is that there are huge participation in Twitter/FB bounties and mostly by those users who spam with many alt accounts using bot to retweet or post. So in the end, you will get much less stakes than expectations.
Whereas in case of Videos or Signature campaign, time element comes to play, especially in video making. My friend who join most of the video campaigns tells me that average time to make standard 2-3 minutes video is 4-5 hours. However, if you are daily poster then Signature campaign won't take much of your time.
So my suggestion to you is to go for Twitter/FB + Signature at the same time and leave video or blog ones.