Can you define "better" or "worse?" Historians don't often think of events or reigns as "better" or "worse" from an outside view.

I'm going to say that Octavian/Augustus took Rome to heights that it likely would not have achieved without him, given the state of the res publica. By that point in the Republic, it was apparent that even the most drastic of actions intended to restore the Republic (Sulla's dictatorship, the assassination of Julius Caesar) would not find success in the long run.

I need not talk about Augustus' record as a statesman and ruler. If you'd like a little more information on it for your reading pleasure, I would suggest the Res Gestae Divi Augusti.

However, I see what you're talking about with your mention of Caligula and Nero. Augustus was a proponent of adoptive succession for the role of princeps, and actually managed to end up with a competent successor in Tiberius despite the deaths of three (not officially) designated successors prior to Augustus' passing. Caligula and Nero both acceded to the throne primarily due to blood ties, as opposed to being adopted by their predecessors based off of a meritorious record of public service and aptitude for the position. Their failures cannot be linked to the model of succession that Augustus created.

Edit (for clarification) The Res Gestae is a record of Augustus' achievements, written by Augustus. As such, it should be read critically while remaining keenly aware of the fact that these are Augustus' words, portraying his life as he wants the people to see it. As such, it offers an unparalleled glimpse into how Augustus himself wished to be perceived by the Roman populace.