As I mentioned elsewhere, I just activated the satrad in my new car. Previously I was using the aux input with the phone app. But this car has a display screen, and if I want it to display anything useful, I need to put it in sat mode.
Update. Being that my "new" car is a 2008 model, it's lacking in tech savvy. When I play SXM through my free-trial, I get a 1-line plain text
name of song, and a 1-line plain text
name of artist, against a gray background. In a corner of the screen is a little selection box that has the channel name.
I've discovered the excellent Android Auto app for my Samsung phone. It works well horizontally, allowing me to park my phone in the ashtray/cubby just below the CD player in the center console. When I enter the car, it detects both my car Bluetooth (phone calls) and my Bluetooth audio receiver (music) plugged into the aux input. It auto-launches the app, starts up streaming SXM, and starts playing the last channel I listened to. With 1 touch, I can full-screen it, and it gives me the full info display with album art and everything. I can go up or down channels, or select favorites with 1 touch. I can also easily launch google navigation, and all phone calling capability is linked through my car. It exits the app when I shut-off the car.
What really blew me away was when Mrs Scotch sent me a text, the Android Auto app put a big banner across the phone with the sender's name, and gave me the option of reading the text to me. Then Google assistant asked me if I wanted to reply, I said yes, then I gave the reply, it asked me if I wanted to send it, I said yes. My car doesn't do any of that.
So, in short, if I end up sticking with the Android Auto app, I will let my free trial end, and I won't need to do a satellite radio sub.