Musing would be in the top 2 for sure as it is all about personal preference and function. I don't use the others as much as I use musing as they don't interest me in the same way. i find musing entertaining and actually learn quite a bit at the same time. It is a bit like general knowledge on steroids and you get rewarded at the same time.Musing's rewards are fair and decent like busy.org. Obviously I use Steemit on a daily basis but I have found that I am spending more time in here these days.