The underlying Tech I believe is just QEMU/KVM Virtualization, They do it at a massive scale but...
They also make heavy use of Docker for their "single click" applications
They have a Custom written proprietary software that interfaces with KVM stack to do the deployments so I do not believe that code is out there.
Virtkick I believe is attempting a DO Style open source management software
I like XenServer. It's an excellent product with a huge community base. It's like the older, more promiscuous, less talented version of VMware. If/when you are ready to add support, it really isn't very expensive.
With that being said, I've been itching to get my hands on a greenfield OpenStack build project. I am partial to Ubuntu so would probably go with their product if I do get to play.
If you are feeling frisky and the word Alpha doesn't scare you - https://www.virtkick.com/ is a very new product that shows some promise.