To me it concerns such as: - how fast is it changing? Am I going to have to re-learn it every 6 months? - how good are extensions for this language? Will people still be supporting their gems (for example) 2-3 years down the line or will it be a wasteland of abandoned relics? - will a new language have significantly better native libraries that will allow me to do more straight out of the box? - will a new language allow me to do more in fewer lines of code, thus decreasing the amount of mistakes I make? - will there be tons of questions asked about this language so I can google for answers to my heart's content?