Dokku is great for splitting up a VPS for a couple of side projects (I used it on a Droplet from DigitalOcean to host a hubot, single page app and Sinatra app).
I guess the renewed interest is in light of Heroku's rumoured price changes^ and Dokku could be a good alternative for light/personal use. It's not a Heroku alternative in the general case though.
^ Heroku is restricting the free tier to 12hrs/day: http://www.octolabs.com/blogs/oc...
Great for teams and developers who create and deploy more often.
Pros:Easy SAAS apps deployment, increase productivity
Cons:Few third party plugins