I have Sirius and love it! I have the Kenwood H2A hooked to my stock HU using the Soundgate AUX adapter. I have the antenna on my rear deck next to the third brake light as well, so you can't see anything outside the car. The dock and tuner are monted in the center console cubby, and I have everything hard-wired so I can conceal it by closing the cubby door.
The sound quality is excellent, and the crap about bad reception in bad weather is exactly that, BS. It works great everywhere I go except under a large bridge moving slowly or under really really heavy tree cover. That could be because I have the antenna inside the car though. Someday I might break down and put it on the roof, but not until spring time at the earliest.
Sirius has excellent programming, I never have a problem finding something I want to listen to. The SJ's really know their music, and actually have personalities. And of course, there is not a single commercial to be heard on any of their channels (with the exception of their own promotions, which are only a few seconds long). Plus, you can listen on line at work or wherever you are if you have internet access but no tuner handy!