I don't really like any of them.
I am an Albany-based coffee & tea supplier who is deeply engaged in local social media marketing efforts now. I think Facebook and Instagram might be my favorite, since they are set to be the most popular and mainstream platforms for B2B marketers. I like Instagram probably the most for its user-friendly navigation and great options for creating signature photos from boring images captured on my smartphone.
It's torn between Facebook and Twitter, actually. While I like Facebook in the way that I can share longer posts (unlike the 140 character limit on Twitter...still wondering when or even IF Twitter10k will happen), I'm not often in the mood to Instant Message people, which is what I like about Twitter more.