I've just bought one. I bought it for £6k, 2.0lt Sport TDI 170PS, 2007 plate, 78k on it. One of the injectors did fail on it just after I picked it up (I managed 38 miles) but the garage replaced it. But, if you're looking at one with 148k on it, I would have thought it will be fine!
As for the car. Apart from being big, I LOVE it! It's nice and smooth when driving it normally and even being a 170, gets high 40's mpg from it (my number 2 average on it at the moment is 45mpg I think, but I've done quite a lot of sitting around waiting with it on and driving in town). But then, when you plant your foot the car just goes. I went from 25mph up to 70 in 3rd in about 3 seconds! The car, for a diesel, even sounds pretty good!
The car in general is pretty good too. Lots of space in it, both in the front and back. It has an electronic handbrake which is a bit strange but nice when you get use to it. Stereo in mine is pretty damn good for a bottom of the line stereo (I have an RCD300), it has auto lights and auto wipers, I dont have cruise in mine which it a PITA, but I'll get use to it.
It is a big car though, so it depends how much space you have.
It just about fits in a space when I go shopping too