Depends on what your motivation is. If your goal is to maximize your job prospects or financial outcome, it's probably not a good idea unless you are interested

Depends on what your motivation is. If your goal is to maximize your job prospects or financial outcome, it's probably not a good idea unless you are interested in going into academia or research. If you want to spend a few years of your life immersed in an environment with smart people working on interesting problems, go for it. Getting a PhD in Computer Science was a great experience for me, but it's not for everyone.