Oh Pandora, how I wish I could quit you. I pay the folks at Google Music for their services, and I know they work hard. They even include music controls in the notification bar and the lockscreen, which you seem to take absolute joy in withholding from me. But on a roadtrip or an exercise session, I always come back to you - years of curated music stations are hard to let go. At least you seem to be updating regularly. The 5.8 update to Pandora adds the 3rd-party Google Now card that was teased back in January.
The actual implementation seems to be pretty similar to the notifications that Pandora sometimes gives you, offering up your own stations or curated playlists. You can disable them if you don't find them useful. There doesn't appear to be any way to trigger them manually, so I can't really test them out - you'll probably see them a few days after you update the app. If you aren't seeing the update in the Play Store, we've got a copy of the new app over on APK Mirror.
Other changes include "Updates to make your Chromecast experience on the big screen even more seamless," though I can't see any changes in the actual casting interface. A few unexplicated bug fixes round out the official update log.