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I have a Sony unit similar to the one pictured. Got it for $188 @ Wal-Mart.
Works great with my iP4, pairs automatically, plays all sounds (iPod, navigation directions, Pandora, etc) come thru if set to "BT Audio", and the unit switches to "BT Phone" mode automatically when a call comes in. (has a built-in mic of reasonable quality)
I did have the iP4 and Sony get a little weird once, (stopped auto-pairing) so I selected "Forget this Device" on the iPhone, re-paired, and all went back to normal.