Brendan, the good points are a given and you wouldn't be considering a Maserati if you didn't appreciate them, so the not so good points...
The suspension setup is very four seater GT. Cornering at speed can be a wallowy affair, but smooth early turn-in does help.
The paintwork on my 4200 (MY'04 Grigio Nuvolari) was very soft and so attracted stone chips at an alarming rate.
The satnav is cr@p.
The wheel bolts are cr@p.
The prescribed tyres can often be impossible to find, but good alternative are available. (Falken and Vred's)
The CC gearbox is awful in traffic, but you do get used to managing it. (keep it in sport mode and avoid auto at all costs, the car'll thank you in the long run)
A clutch change is expensive by any measure, and you'd be a fool not to change the release bearing and bell / spigot bearings at the same time.
Get used to cabin squeaks. You may think it points towards poor build quality, and perhaps to a small extent that's true, but it's mainly due to heat fluctuations affecting the leather.
It's Italian, so you'll soon find that your local dealer / indi' is on speed-dial and on your Christmas card list.
Other than that it's all good!