In case you missed the news, Google is shutting down Picasa on May 1, 2016, forcing everyone onto Google Photos or perhaps encouraging them to use another service all together. If you are in the later group you might want to consider Forever Historian. I have also heard good things about the far more expensive Adobe Lightroom for photo organization.
Why is Google shutting down Picasa? The simple fact is that Google relies on advertising to support its business, and somebody at Google has determined that they can show you more advertising and better monetize your photos if you are using Google Photos. Google is not a photo preservation and they will support a product as long as it makes sense from an advertising perspective. From their perspective there is no reason to continue to support Picasa.
For more details on this announcement see Google is shutting down Picasa on May 1, 2016 and Google is shutting down Picasa in favor of Photos.
All About Images Blog 
Boo! hiss! I liked Picasa. Used it for collage photos.