When Apple introduced OS X Lion, it changed the default view of the user's home folder to no longer show the Library folder. This change arguably offered less clutter; however, this resulted in a number of people frustrated when needing to access contents of this folder.lo
Apple did include a link to the Library folder in the Go menu of the Finder; however, even this was relatively hidden, and required you hold the Option button when clicking the menu to reveal it.
For those who needed to access their Library, workarounds included using the Terminal to run commands that changed its hidden status, or by revealing the folder through the built-in and supported options, and then dragging it to the Finder sidebar or otherwise linking to it.
However, in Mavericks it appears Apple has recognized the need for some users to have the user Library folder readily accessible, and has added an option to toggle its presence in the Finder.
To toggle this option on, simply open a new Finder window and go to your home folder. Then press Command-J or choose "Show View Options" from the View menu. When done, you should see an option to "Show Library Folder" among other view options, which can be checked to reveal the Library folder.
This feature will not be needed for all users, so if you have no need to regularly access the Library folder, then you can keep it hidden, and accessing it will be the same as in Mountain Lion. However, if you are regularly accessing configuration files and other details in your Library, then you can now keep it visible without having to resort to Terminal commands or third-party utilities.