We're working on a new alternative! If you know your way around WordPress, you can try Zero BS CRM... we're building it on WordPress because many of us digital people use it so frequently, it just makes sense :)
http://zerobscrm.com or https://wordpress.org/plugins/zero-bs-crm/
(It's free, with paid extensions.)
Current version works well, and we're still developing on it every week, releasing a kind of "v2" MVP in the next few months. We're open to feedback, and keen to make this a solid base for all of us who know how to self-host stuff and deal with customers!
Key principles we're building ZBS with: