Sirius has plenty of commercials, especially Howard Stern. Not as much as radio, but still enough to be annoying.
Yes, HD Radio has commericals. There are extra channels (compared to regular FM), but otherwise it's the exact same programming.
The quality with HD radio is better (than regular FM), but not amazingly better. It's nowhere near the quality of CDs, which is kinda what I expected when I got it.
Between the two, I'd go Sirius. You already have FM, and the jump to HD radio isn't a significant one compared to getting a shit ton of new channels with Sirius.
Just don't expect it to be commerical free! I don't know why people think that.
Last edited by jluv; 12-18-2008 at 08:50 AM.