I feel for you guys - and I say this sincerely having searched and searched for a diesel 2.0, or preferably a 2.5 Quattro, some years ago and being unable to find one ended up with a 53 plate, 2.0 (non-turbo) petrol A4 with 60k on it instead.
I'd based this on having a 54 plated 2.0 diesel B7 A4 as a lease car, and a 2.5 diesel Quattro A6, again leased, some years before that. I often wonder if the 2.0 was one affected by the oil pump problems. I had it just under 2 years, and of course as a new car it was fine. The A6 on the other hand had some minor problems - and of course I've since found out about the chocolate cams on those.
Lucky me. Would I buy a 2.0 170 diesel? Probably not. But then again, what % of these cars are having problems?
That said, the A4 I have hasn't been without it's costs and niggles - but with 145,000 on it I'm reasonably happy overall, and it just puts a smile on my face every time I drive it. And yes, it's hardly a performance car but it moves well enough and returns 33 mpg overall. The overall build quality is grand, and other than an occasional mystery minor knocking from the front suspension, it's solid, doesn't rattle and is rust free - apart from what I know to be a pattern front wing which is starting to go.
And here's the problem - we like these cars because they are reputed to be solid and long lasting. But the reality is that we're getting stung with poor engineering and problems caused by trying to make a small, inherently dirty engine, be clean, refined and with high performance. The diesels of old ran and ran - and rattled, smoked and sounded like, well, a diesel. But they weren't festooned with DPF's, balance shafts and all the other gubbins of a modern diesel car.
All this said, a pal has a late model Mondeo and loves it. He's an ex BMW owner who had to get a bigger, cheaper car when they had a family. he says it's great. I had an old 1.8 Mondy years ago - it just ran and ran, but was also bland and boring. Cost me .66 a day (ex normal service parts etc - so that was depreciation and repairs) over 80,000 miles in 5 years though! But I much prefer the A4. But that will cost me far more than the Mondy did.