Hootsuite sucks. It's clunky, and the UI is horrible.
Buffer writes great blog posts, but I just don't see the value in its service.
HubSpot, if you can afford it, is what I enjoy using the most to post to social media because of its Social Inbox.
For Pinterest and Instagram, Piquora looks promising and so does Postris.
Read/skim these articles: -https://blog.kissmetrics.com/automate-pinterest-marketing/ -http://www.inboundio.com/blog/ultimate-list-23-marketing-too...
Another great tool I love for social media management is sproutsocial.com.