I mainly use one of the key music services not supported, multiple people and rooms, line-out to my PLAY:5 (audio from Alexa to the PLAY:5 over the network would be fine), and grouping. All of these things are broken or not supported by the public beta. The audio ducking is a disaster and has caused me, and others like me, to have to disable the skill.
Basically I use Sonos as it was intended, for the things that made it popular--with room and grouping functionality, nice sounding audio (rather than the audio out from Echo devices), and great integration across music services.
How do I find out when the integration with Alexa starts to be not horrible? I don't want to monitor dozens or hundreds of unrelated posts on forums. The announcement of going from beta to GA will be big enough, but doesn't yet seem likely to be the right announcement. The private beta went public without any of these things, even after an extended amount of time for feedback and development.
Creative or tricky ideas are fine, as long as they work. For example, an rss feed filtered to certain keywords would be acceptable. It would take a few minutes of work, but might serve a purpose for a year or more.