Sabayon vs Ubuntu
From WikiVS, the open comparison website
Sabayon's package management system installs software from source code, or ebuilds which work like binaries. Ubuntu uses repositories of pre-compiled software.
Ubuntu is many times more popular than Sabayon. This may mean that if you have a problem with Ubuntu, there are more people available who might know how to fix it and might have encountered the same problem. Sabayon's community is smaller.
Sabayon is a rolling release, continually updating to the newest version. Ubuntu doesn't.
Sabayon is not ran by a for profit company.