It is well known that the 2.5l Td (basically the same engine as the 2.5l n/a plus a turbocharger) has a bad reputation regarding reliability. Having said that, if you don't overstretch its limits it isn't that bad at all. Stick to the service intervals and don't let it get too hot. The 200Tdi is by far the better bet, though.
Just my 2c...

