While 99% of people on Instagram are pitiful, there is some pretty funny and interesting stuff on there
use it more
If I must choose, it would be Twitter. It can at least be beneficial for businesses at targeting a specific audience as well as for generating people with similar interests to your website. I never used Instagram as I do not find it interesting. Correct me if I'm wrong, but is it not just a bunch of people posting random pics of themselves for no apparent reason?