I'm setting up a virtual machine using ubuntu 14.4. I was delighted to see that in the software center, SJ was the FIRST app displayed, at the top of the page under What's New. Very good.
When I went to install it, the button said "Pay", though SJ was listed as Free. No problem, I thought. But the Pay button led me to a ubuntu One log in page. One needs to have a central account with ubuntu in order to install SJ from their servers.
I'm installing manually.