I've got a 2.5 N/A (no turbo) with 155,000 on the clock. It runs great with no leaks besides the oil filler cap if it is revved to hard. It is generally happy to run on a diesel / veg oil mix straight from the fuel tank with no extra kit, just takes a little longer to start up from cold that's all.
The only problem I have had is with regards to loss of power on hills. I had only been getting 15mph up some hills, and the speed massively decreased on the slightest incline on the motorway. I have since re-plumbed the fuel line changing the banjo nut, fuel filter, filter casing and seals and it is pulling up hills at 30-40mph. It's amazing how much an effect the slightest air leak can have on its performance.
The major downside with the 2.5 Turbo is that it is just a 2.5 N/A with a turbo block bolted on. It wasn't specifically designed to handle the extra power but it is perfectly capable. You may have to replace the odd push rod or crankshaft once in a while because they have a tendency to go under the extra strain.
Generally speaking it's a solid engine and very serviceable. You can get at everything you need to be able to get to without cutting your hands to bits. It's a strong performer, but it doesn't have the horsepower or the torque of a 200tdi or TD5 for example. I think it does have the fastest acceleration out of the lot if that's of any consolation!
Good luck
-Pos