No Ella, it is not good.
1. He broke the law. When a judge orders you to stop doing something because it is a against the law, you are supposed to stop.
2. He is a hypocrite. He went around saying he was going to enforce the law. Then he broke the law. He didn't just break the law, he defied it. He told the law to go f*** itself.
3. He took away the rights that people have. You might not mind that he took away the rights of undocumented immigrants (the law does). Arpaio also took away the rights of legal immigrants. And, Arpaio took away the rights of American citizens.
Arpaio should have gone to jail. That's the law. (Oralloy is technically correct that Trump has the legal right to pardon Arpaio, but that doesn't mean this isn't a horrible decision.)