The dashboard has a new look, and it is quicker to get around than the one it replaces.
Navigation used to be split in two: a sidebar for sections and a top bar for everything else. Which one held what was never obvious, and the top bar had grown over the years into a row of unrelated controls. There is one sidebar now, with its entries grouped, and no top bar. Your workspace, your account and your notifications are all in it, so there is a single place to look and less distance to travel between the things you use most.
Notifications open as a dialog in the middle of the screen rather than a narrow drop-down, with a count on the sidebar entry when you have unread ones. A long notification is shortened to its first few lines with a Show more to open it, so one wordy notification no longer pushes the rest of the list out of sight.
On a narrow window the sidebar becomes a drawer you open when you need it. On a wide one it stays open, since collapsing it saved a few pixels and cost you the labels.