I dont midn having the XM radio but I probably will not renew it when its over. I have a lifetime Sirius subscription on a portable radio that I may just get a car kit for and mount it somewhere in my '12 SR5, I tried swapping the boxes in my Scion tC that I had before the T4R, and after I bought everything to make the Sirius radio work in the tC, I found out that they were going to charge me and extra $175 to switch the subscription to the new radio. :O So I said screw it and just got a car kit for it and used it as a portable one.
Even though XM and Sirius are now the same company they still use different transmission methods. XM uses a few satellites that transmit to ground repeater stations, so with XM the signal may not be any better than with a normal AM or FM radio station depending on how far you are from your nearest ground station, and in my area there are quite a few "dead spots" with XM.
Sirius on the other hand uses solely satellites, and has more of them to transmit the signals across North America, so there aren't any dead spots that Ive found with my Sirius radio, and I drove from Bellingham WA to Central FL 2 years ago when I got transferred. When I was stationed in SE Alaska on the USCG Cutter Liberty, we used Sirius on the boat as well and the majority of SE AK is very remote and we never found anywhere where we lost signal.