https://source.android.com/security/bulletin/pixel/2019-01-01.html here's the link to the changes made in the January patch.... it looks like they just fixed a couple of vulnerabilities in Android 9 for all the pixel's, and made an improvement to the pixel 3's video recording sound issues. They have the first 2 pixel models pretty well sorted..... it's the 3 that has the issues :O
We will be getting improvements to Android 9 though, along with security updates, and we should be getting a few more features from the pixel 3 when they roll them out ;-)