We have a 2010 Limited with the upgraded sound system. I personally think it is a subpar system. I am not an audiophile who demands a million dollar sound system, but I like to have a quality sound system. I've listened to a CD, Sirius, FM, and some MP3's. They all have the same hollow sound, almost a bit muffled too.
The NAV system has been great for us so far. Very, very accurate and easy to follow.
-Mike