Containerization Platform splintering

It was inevitable.  Docker's unprecedented growth was simply too big and too fast to manage.  It was only a matter of time before major contributors and admiring architects started envisioning a "better way" (aka "their way").  Currently, there seems to be a growing list of contenders since Docker released their first public offering in March 2013:

• Imctfy (October 2013)
• Terminal (unknown launch date -- at least as early as June 2014)
• Vagga (released around July 2014)
• Flockport (initial public offering August 2014)
• LXD by Canonical (announced November 2014)
• Rocket by CoreOS (initial public offering December 2014)

Note: I highlight Docker due to its current popularity, but container technology has been around for a long time.  For example, Parallels Virtuozzo Containers were introduced in 2001 [leveraged in Jelastic] and Solaris Containers were introduced in 2004 [leveraged in SmartOS].