Re: 159, Mercedes C, Audi A4, BMW 3
Ultimately it's all down to what you can live with. I love Alfas, but I can appreciate other car marques as well. Cars are such personal choices.
For instance - I drove a Lambo Merchalargo (or however you spell it) on a track day. Inside I though was bland. Fast but driving it I had no real sensation of speed. A boring car IMO. Just style over substance for me. Not worth £150k or whatever it costs. Aston was much nicer.
Anyway I do love Alfas, after all I'm on my 2nd 156. But I don't rate the 159 ATM in it's current state. Lovely to look at and nice to drive, but it still has too many faults for me to consider getting one (which I was until Hunter had brake and other problems, and I know they are very rare, but it put me off). Also high C02 and lower MPG.
Some people like the new A4, others don't. I think the new A4 or Jag XF is something I could go for. Not Merc C class or BMW 3 series though. Most car mags think the A4 is a step forwards, only the odd one think not.
All cars have some issues. It's how dealers deal with them and fix them.