I've felt ambivalent about the native Dock since it showed up - a love/hate relationship at best - but Trampoline is a fantastic alternative. Easy to use, easy to show/hide, easy to add/remove items from its circle - highly configurable and, unlike Dock, doesn't show up when I don't want it. The developer has thought carefully about its behavior and taken user choice into account at almost every turn. I recommend it as a great Dock alternative.