When comparing Ubuntu LTS vs SmartOS, the Slant community recommends SmartOS for most people. In the question“What are the best host OSes for Docker?” SmartOS is ranked 5th while Ubuntu LTS is ranked 6th.
Ranked in these QuestionsQuestion Ranking
Pro Most users are already familiar with it
Ubuntu is the go-to Linux distro for most people, so there is a sense of familiarity and comfort in using something they have used before.
Pro Good PPA repositories available
PPA repositories allow you to install the latest version of your preferred software while keeping the rest of the operating system "stable".
Pro Just works out of the box
Lots of support for hardware, lots of pre-installed software, and a smooth install process means less time downloading drivers, less time digging through configuration files, and less time deciding on software to use just to get up and running. It also means less time digging through forums looking for support.
Pro Lots of support
As the most popular Linux distribution, there's a wide range of sources for support online if you ever need help, including the Ubuntu Wiki, Ubuntu Forums and the Ask Ubuntu Stack Exchange site.
Pro Great Long Term Support release schedule (2 years)
This allows for users to always have a new supported release available without long unkown wait times in between.
Pro Bare metal containers
Pro Great container isolation
SmartOS Zones provides excellent security through isolation on bare metal.
Pro Easy networking
Each container gets it's own IP and net stack.
Con Relatively high system requirements
The default Unity desktop environment is a resource hog which requires hardware accelerated graphics rendering in order to run smoothly, making out of the box Ubuntu unsuitable for low end systems and older hardware. Even mildly aged hardware, you'll get far better performance out of a lighter desktop environment like LXDE or XFCE.
Con Not linux
Many users prefer the familiarity of Linux. (SmartOS comes from Open Solaris)