I have SiriusXM in my current car and had it in a previous car. I had six month subscription included with the car purchase, I played with it, but when the subscription expired I did not renew it. I did not find much to my liking on SiriusXM that I cannot get on streaming radio, I did not care about Howard Stern, an the selection of news was very limited, basically the same ABC/NBC/Fox as on OTA television, plus BBC. But I could never catch anything interesting on BBC when I was driving to work and back.
It costs more than Netflix, and it cuts out when you drive under overpass. Its only benefit is that it works in remote areas where there is no mobile phone connection and no FM stations.
I agree about podcasts and audiobooks, these are better experienced on-demand. Curiously, I found many great podcasts on BBC, these originally were radio shows, made available on demand.
I also listen to The Long Audio Read from The Guardian.
I used to listen to programs on education from APM, but some of them seem to be heavily influenced by sponsors, in particular when they talk about charter schools or personalized schooling.