Ask anyone who's used a Mac for a long period of time and they'll tell you that Cocktail still remains one of the best all round admin tools out there.
Cocktail can do all your essential maintenance tasks from clearing your cache to controlling sleep times. There's nothing new in Cocktail that you can't do in Terminal but Cocktail makes it so much easier through its GUI. Many of it's functions and tweaks will remain a mystery to basic users though - options such as whether to switch on or switch of journaling and the network options are aimed more at power users.
Nevertheless, for those that want more control over how their dock works, their startup sequence and other OS interface related issues, Cocktail gives you immense control. The Interface options are perhaps the most useful allowing you to select a range of different features such as Finder, Safari and Mail and tweak them to your own liking.
Some users will complain that what Cocktail does for a modest fee, other apps do for nothing but as an all round system maintenance tool, especially for power users, it's one of the best out there.
- Added OS X 10.9 Mavericks compatibility. Note: Cocktail (Mavericks Edition) requires OS X 10.9 Mavericks to run.