Faults experienced in 96k
I clocked up 96k today on a 2007 159 JTDm so I think I can give you a considered opinion on build quality and reliability...
Battery failed at around 10k but was replaced under warranty.
Changed Cam belt at 68k miles and just caught a failing water pump in time.
Noticed that wing mirrors appeared to be losing their chromed coating round the edges after around 2 years.
Power steering pump started whining at 94k. A new fluid reservoir and fluid change to the correct Tutela GI/R appears to have cured the problem. (should have been a recall)
The leather seats are amazing and hold up incredibly well.
Glow plug heating system unavailable warning light at 94k. Replacing one failed glow plug cured this.
Poor paintwork has always been my major gripe. Had the rear panels painted and Ford Mondeo arch protectors applied to protect against stone chips. The paint is poorly applied and about 1 micron thick!
I have serviced the car myself since the warranty expired and it's actually quite a nice car to work on. I have the Alfa software (paid version) and can do any diagnostic work if required but apart from service reset and a forced regeneration on the DPF, I've not had to use it.
Reliability has been excellent but I think the water pump, the fluid reservoir and wing mirrors show that Alfa still need to be a little more quality conscious in sourcing parts. They also have a long way to go in bringing paintwork upto German standards. The 1.9 diesel engine is as good as anything out there so overall I'd give the car 8/10. A good score but I won't buy another until they sort out the paintwork issues.