As ppl already mentioned its your personal choice and need for features.
I've premium sound with ipod/bluetooth, no Nav and im really happy with that.
I'm driving a loaner (with nav) for the last 4-5 days and I'm not liking the big hump in the center...again its my personal opinion.
I personally prefer Garmin GPS because of their algorithms to find routes.
$100-200 GPS system can be replaced anytime with the changing technology.