I would NEVER, EVER, pay that much ("rack rate") for sat radio - it's just NOT worth that much to me. Now, something like the $77/year deals that people are getting, I would probably do.
But it's all a moot point for me, because I'm on XM lifetime, & was able to get it at the $399 price RIGHT before they jacked it up with that music royalty BS charge.
Not only that, due to some BS I went through with their terrible (no) customer service awhile back, I was able to get the best of Sirius added on to my lifetime sub at NO extra charge - so I ended up getting it all for $399.
Since I will be keeping this car (radio) for at least 5+ years, I do think I'm getting my money's worth - but I would NEVER do another lifetime now, as I understand it is MUCH higher than what I paid now.