The Beta has been updated with the following changes:
Emoticons show up now in Big Picture
Added user definable action sets for legacy games.
Users can now add additional action sets with their own sets of bindings. Action sets can be added/deleted/named as appropriate and selected via a binding. Note that unlike mode-shifts, action sets completely replace all currently active bindings, and can have their own mode shifts and so forth.
Added New Controller Action binding types which will expand in the future with bindings that are not specific to the game, but rather higher level, as noted below.
Added Change Action Set Binding - sets the action set to the next or a specified action set when used.
Added Show Keyboard Binding - shows the on-screen keyboard
Added Take Screenshot Binding - takes a screenshot
Removed hard coded desktop keyboard shortcut (stick click) and replaced it with controller action binding in the default desktop configuration.
Fixed some cases of non-steam games not applying controller settings. Ensure that "Allow Launchers" option is off for this to take effect.
Fixed controllers not turning off on Suspend power mode in Desktop mode which could cause zombie controllers to be seen over wireless
Fixed Horizontal Invert setting not working on Mouse Joystick
Automatically launch SteamVR after it finishes updating
Added the SteamVR tool in the SteamVR section in the Library view
Added SteamVR to the jump list options
Improved scrolling when using the touchpads in the Steam interface while in your HMD