[cm2012]

My instinctual advice is don't do it - the grass is always greener. Most PHDs are never read or cited by anyone and your hard work will collect dust.

My more thoughtful advice is from something Bryan Cranston said. Basically, he said trying to be an actor is ludicrous. You have a high chance of making no money and never getting a break. Because of that, you should only become an actor if, like him, you can't bear to do anything else.