As someone finishing up a Masters and looking to go to law, I would totally recommend it if you're passionate about the subject area. Law school is always going to be there. There is no rush to go. Spend time discovering your passions and becoming a better student before committing to a JD and a life in law.
That being said, in this cycle I'm not sure if I was any more competitive than those without Masters, even though my Masters GPA is about a 3.9. But I personally feel that I am a better candidate now than I would have been right out of undergrad, now having a better understanding of why I want to pursue law.