Ok I couldn’t test Auto Backup, but the Picasa geeks have a good summary of the key issues. I agree Auto Backup is probably not for me. If you do want to use it please understand that it is not really unlimited! (make sure you read the fine print, full size images will count against for Google Drive limit). I see it is more a strategy to collect all of your photos onto the web, specifically onto Google+. This might be fine if you are only generating photos from a mobile phone (and maybe a Tablet or iPad) and it will let you view your full collection from those devices. At least the default is private, but you can easily share through Google+, There is also an update to maximum file size limits for uploads, now they can be up to 50 MB or 100 megapixels.
Something a lot of Picasa users may not have noticed was that “Edit in Creative Kit” was discontinued back in October.without any notification that i was aware of. The creative kit was the Picnik software, one of the early and at the time very popular on-line photo editors, Google had purchased it some time ago but seemed to do little more than change its name. In the 137.69 build the Edit in Creative Kit" key has been removed. You can still edit your photos on line with Edit Photo inside Google+ Photos or let Google do the enhancements for you with Auto Enhance and Auto Awesome.
These three “updates” are essentially about Google+ Photos on-line not Picasa on your PC. So were there any changes for your PC version? Apparently so, there are updates for RAW support to include newer cameras. Also there are patches to image handling, to fix several issues in RAW, TIFF, and JPEG handling. The RAW formats I use are already supported and I’m not sure of the circumstances that the new image handling patches will make a difference so these also may not make any difference to me