The problem with USB as you menton is you need a playlist. I have a Galaxy SIII with a 64GB microSD that is over half full now so approaching 500 albums. The phone connects via BT to the radio and has a nice display of the albums sorted by name or artist.

Usually I select an album then switch to either GPS or Torque Pro display.

When I bought my XF in '13 I thought it was going to take both a phone and a tablet but since then I bought the SIII with a 5" display and that does everything. well (still have a 7" tab in the Jeep but now have a phone mount also.

At first I used a CD mount with a clamp but since then have found that a magnetic mount does not lose the phone on a hard shift.