I've had my 06 model GT jtd for nearly a year now & use it as an everyday car. I had it remapped by red dot a few months back. Superb. The oil level gauge on start-up on the dash is not particularly accurate, so still check using the dip-stick.
My drivers-side windscreen wiper failed a couple of weeks ago & was fixed under warranty. This is another fairly common problem.
I found the clutch to be OK, but then I do have big legs.
Yes, the occasional rattle, but nothing else major.
I've had FAR fewer problems with my 2 Alfas (a Brera & now my GT) than my mate has with his same-age Audi A3, which are supposedly "super-reliable???".
As others have said, a good independant for servicing is a good idea, as is the buyers guide that RossoGT pointed out.
Its a VERY good all round car.