It is (usually) good. It refers to a person whose natural personality is relaxed, mellow, cheerful, friendly, and undemanding. Here is an example: "My first boss was very easy-going. He didn't say a thing if you came in a little late, and he didn't mind people dressing casually. My second boss was the exact opposite: an intense, hard-driving perfectionist."
It could be bad if the person you are talking about needs to be careful and precise. "My first boss was too easy-going. Everything was always disorganized and chaotic, and nothing got done."