XCARLINK is what I have and I am pretty happy with it. Crystal clear, bluetooth capability, aux input jack. When I installed it I was a noob and it took me all of 30 minutes. Very easy user interface(once you read the manual beforehand)...
I'm assuming you mean for iPod connectivity? If so sound wise there will be little to no difference, the difference comes to how the unit interacts with the steering wheel controls.
Standard - Expensive, use of playlists is annoying
Xcarlink -Pretty much the same as the Dension/DICE etc..
Parrot MKi9200 - Great if you want hands free and track titles displayed on it's little screen, if not it's expensive just for iPod