Having had an MDI on my last Octavia I thought it was a major omission from the option list for the UK spec Yeti inspite of it being available in other markets including, as far as I know,Ireland. I was told by the dealer I got my car from that Bluetooth was the way and I should get an iPhone. I wasn't entirely convinced though.
After getting the car I was setting up all the options and managed to pair my ancient Nokia phone to the built in hands free system which works incredibly well. As a bonus I found the BT audio function on the radio was enabled so I can play the same tracks from the memory card in my phone as I have on the SD card and the CDs
Ithink that one advantage of the MDI is that it powers the iPod. On a long journey playing tracks from your phone can flattenits battery. You won't get that with the MDI.
Also don't forget that the steering wheel controls do not work when the ignition is turned off but bluetoothwill remain active and controllable from the radio until the ignition key is removed.