As for 'scare stories' that's all they really are these days, generally speaking. Fiction, in most cases. I've had five 'modern' Alfas since 2003 and all have been almost perfect and absolutely reliable. I can't quote statistics but I'd take a punt that Alfas are no worse than the competition in this respect. Yes, people have major problems which put them off for life but then so do drivers of BMW, VW, Merc. etc. etc. etc.
Specifically the Brera and 159 are pretty much bomb-proof and even though there are now some high mileage cars out there I'm not aware of there being any major recurring problems being reported.
In the Brera your only diesel option is the 2.4. In both the Brera and the 159 the 2.4 can suffer from Diesel Particulate Filter (DPF) related problems but I'm led to believe that this isn't specific to Alfa but more to do with the DPF itself, which I think all large diesel engines now have to be fitted with. Though my own 2.4 has been flawless since new and is now at almost 20k miles.
Mpg in the diesels is pretty poor compared to the competition but this is more than made up for by the smile that they put on your face. In the 2.4 expect 32mpg average if your driving is mixed or 38mpg if you do a lot of motorway stuff. Expect better in the 1.9 159.
Driving comfort is good. On Monday just gone I drove 400+ miles to Milton Keynes and back and was fresh as a daisy when I finished. I think all Breras/159s have cruise and if you want built in bluetooth then you need the Blue&Me system. And I don't think you'd have a problem fitting golf clubs in either car.
Hope this helps?
Keep us informed how you get on.