Yet to experience DAB on the move - let alone in my soon to be collected CX-5.
However, DAB is NOT robust when it comes to signal strength and reception in UK. It can work in one room in a house and not in another, then drop out when someone walks by the receiver, I can only imagine that on the move is going to add to the issue.
If you are in a strong signal area then fine and you'll get great sound, otherwise I suppose it's back to FM. This is why the audio analogue broadcasting switch in the UK has been pushed back!!