I currently own a 2013 Dodge Durango, and previously owned a 2012 Dodge Durango. Both with UConnect.
Using an iPhone 4S and iPhone 5, I've found that the UConnect in the 2012 Durango allowed for using phone calls, Siri, navigation, voice mail, and more, but the music playing via the BT setting in the car gave poor audio quality when playing with the iPhone 4S. Didn't try with the iPhone 5 for the BT music playing from the device.
Using the same iPhone 5 with UConnect in the 2013 Durango, I've found that I can still use it for phone calls, but Siri, navigation, and voice mail no longer play through the car as they did before in the previous model. The sound quality when using the BT setting to remote play from the phone has much improved quality and clearer. The sound quality may be due to being an iPhone 5 over the iPhone 4S, as I had read on a Dodge Forum that the iPhone 4/4S had an issue with audio with streaming music to BT with the UConnect.
The main difference between the 2012 and 2013, is that the 2013 has the GPS/Nav in the stereo system, which was not part of the 2012. This may be part of the reason that only the phone part works. It is annoying to say the least, as it defaults to UConnect as the output audo source, so I have to manually change to iPhone each time I go back to voice mail to hear anything while the car is on. As well as have to manually change Siri's audio source input, as it too defaults to UConnect, as it doesn't switch from satellite radio to input speaker mode in the 2013.