Oh don't get me wrong, 3.2 has its faults as we all know. But they are much better documented on here. TB had agro with his [carrots on]Traaarcderrr[carrots off] iirc.
Just a little. How many times did we have the engine out?

Thing is, the 3.2 very rarely has a major issue. OK, it needs cam belt changes and the occasional cam cover gasket.
The 2.5TD has an troublesome cooling system and, at the slightest hint of overheating, the head warps. Fine if you never have a problem, but, if you do, it turns into months of looking for water leaks and chasing your tail before the inevitable.
Plus the sensitivity to oil changes. If you're lucky enough to get one early in its' life before it's been abused, then fair do's, but that isn't going to happen any more. The chances of finding a TD that hasn't had at least one owner who's had it for a couple of years yet never lifted the bonnet are slim, hence the rot has set in with most of them.
BMW diseasel lumps all pretty much have the same faults. Even in BMW cars. 120k on and savings for disasters have all gone. Sooner in some cases. Especially among those who still commute.
The Omega's era of TD is reliable in comparison to the later common rail engines yet not really economical enough to make it worthwhile. I would imagine the common rail engines probably go some way to sorting the economy, but look at the hassle people have with those!