I had XM in my car when I bought it in 2011. I didn't use it much for anything but trips. I found that the channels tended to repeat after awhile, not bad on shorter trips but noticeable on longer rides. They also had commercials which I thought was wrong on a service I was paying for. Finally, it would cut out under bridges, in tunnels and terrain features where there were high sides flanking the road. The worse thing was just like cable the price kept creeping up on me. I dropped it because it was seemingly more trouble than it was worth to me.
Our trip north was from the 2nd to the 15th of June so I figured I would try out the free service while we were driving in the coach. I was never able to get it to come up so I wasn't able to try it. I'm thinking it was something I did wrong but I really didn't need it so money saved in the long run.