The official update could be just 1 to 2 weeks away from getting rolled out, although by the time it reaches everyone, it could be quite a while. As far as the changes you that can expect from the update, it is said to be similar to the changes found on the Android 4.4.2 update for the Samsung Galaxy S4 found on the Google Play edition. Status bar icon colors have been changed to white, and there have been changes to the lockscreen including adding a shortcut to the camera, and the use of full-screen album art when playing music.
Keep a few things in mind. The test firmware will wipe your current data, so back up your phone. The good news is that installing this test firmware will not void your warranty, although it might brick your phablet if you don't know what you're doing. If you're not sure about installing the ROM, your best bet is to wait for the official release. Otherwise, click on the sourcelink for instructions on how to load this ROM on the SM-N9005 model of the Samsung Galaxy Note 3.
source: SamMobile via AndroidAuthority