There’s a certain amount of ladder kicking involved in telling people to choose boring and beige technologies after you started up your career chasing after new and exciting shiny things. Every developer should spend some time working at the bleeding edge, so they know how it feels to get cut. The best time is absolutely at the beginning, when you’re a fresh grad and have the energy. You have the rest of your life to…
A lot of new tech is shiny and provides legitimately useful benefits. Think the new wave of frameworks that started with Rails and Django.
There's a lot of shiny tech that has been a gigantic waste of everyone's time, like MongoDB and people trying to shoehorn MapReduce into every possible computation.