The D5 has a pretty bomb proof reputation, I’ve got an older and higher mileage example and thus far it’s been faultless whilst delivering good performance and - for its size - good economy, by far the most comfortable car I’ve driven.
The 2013 courtesy V70 D5 Lux I had whilst my A4 was in for repair was most definitely NOT good for economy at all. It was surprisingly terrible on fuel, and didn't really have the performance to back up the level of thirst it had.
Comfort though, I can't deny that it was incredibly comfortable.