all i know is early ones had crank/big end problems, later ones were supposedly better but there are plenty stories of them going bang
at 80-90k..... advice is generally to go tried and tested petrol, but main thing is a FSH and stick to regular servicing at the recommended intervals..
for every story about 200k plus with no issues there are equal stories of terminal trouble.
fwiw subaru aren't going to make diesels after this year. they were late to the party and are getting out early.
draw your own conclusions !!