I'm using an iPhone 4s and a Samsung Galaxy Note in my Explorer. I prefer using the iPhone over the Galaxy Note. The only drawback with the iPhone is no text messages and no photo ID. I don't care about the photo ID, but I use Siri as a workaround for reading text messages. With the iPhone, you can hear Siri over the speakers in the Explorer, so I listen to my text messages that way or to send as well. I actually use Siri a lot since it's nice you can hear over the car speakers.
With the Galaxy Note, it won't work connected via USB. It only works connected as Bluetooth. The Galaxy Note won't show the song or artist information when using apps like TuneIn Radio or Radio.com app. I have a few songs I put on the Galaxy Note, but none of the song information showed on the MFT screen. With the iPhone, the song and artist information shows on the MFT screen when I use Pandora, TuneIn Radio, and the Radio.com app. When I use my iPhone as an alternative to my iPod, song information and album artwork shows on the MFT screen.
I haven't had any Bluetooth connection issues with either phone.