To be able to go back in history and find out what was happening at certain times is the most valuable feature of the product.

Another thing that's good about the product is that it will let you know when your jobs are taking longer than average so that you can foretell that there's going to be an issue coming up. Your SQL agent job is taking longer.

The blocking and deadlock report feature is very convenient to use in pinpointing which query is causing something and what other queries are waiting for it.