defender 2.5 turbo diesel is it worth it?

hi guys
got a quick question
does anyone have any experience with th 2.5 turbo diesel?
Ive been offed one to buy for my series.
ive read that they were self destructive up to when land rover fixed the problem
this has about 170,000 on the clock so its proven something
if it was going to be an problem motor dont you think it would have already lost the fight?
i saw a video of it running and it looked and sounded pretty good.
i know about blind purchases. so any idea what there worth
should i just go with a 2.5 nad?
thanks
aaron