Plank is a great light-weight dock. It doesn’t try to wow the user with tons of addons and 3d effects, but it is simple, clean and gets the job done well. Its one of the elements of luna that almost always draws a favorable comment when I’m showing off elementary OS to friends, family or strangers unfortunate enough to sit near me in a coffee shop.
When I finally shut up and let people play with elementary OS a bit I notice there is one feature in Plank that most users miss. Users intuitively want to click on icons, but some times Plank wants you to scroll. People quickly figure out that Plank uses click to minimize, but they sometimes miss the fact that it uses scrolling to cycle through open windows.
Here is an example. I have two Files windows open. If I click on the Files icon in Plank then it will minimize both windows, but if I just hover the cursor on the icon and use the scroll wheel on a mouse or two finger scrolling on a track pad then it cycles through to the next Files window. This is particularly useful when an application is maximized because it is quicker then right clicking on the icon and choosing a window from the list.