I switched to Debian Stable after using Ubuntu LTS for 6 years, and recommend Ubuntu for beginners. It is stable, best community support, boring and good ol’ reliable, which is perfect to learn Linux and get accustomed to it. Even corporate support and game developers target Ubuntu first. Considering it runs smoothly on a 6 year old midrange Intel laptop chip, nobody is getting that 200% performance boost with other obscure fancy distros.