Augustus was considered a hero in Rome after the Egyptian attacks. During his reign, Augustus also expanded Rome's land. He spread Rome past Spain and Germany, creating more space and power over other parts of Europe. By the end of his reign, he ended 100 years of civil war and achieved 40 years of peace and prosperity. This definitely makes him the best emperor out of the four I chose.
Galba et al reigned 68-69 AD. Right in the beginning of his reign, he automatic call made enemies. He was very strict and serious when it came to his country. Galba was assassinated seven months after he became emperor. He did not do much, but he worked mostly on his military and making it stronger. Even though Galba did not have a very long reign and didn't do as much as most emperors, he definitely did better than others.