It's a fairly pokey car (0-60 of about 9 secs i think), i personally don't like alfa styling so i wouldn't get one.
You have heard mixed reviews because it's one of those cars that is fine if it's been looked after but a bitch if anything goes wrong (parts and fitting are very expensive), alfa's are "legendary" for their rust problems, thankfully the 156 is much better for this than the older ones but you still must keep an eye out (as with any car you buy)
Get one if you really like the style, otherwise there are prob better 2 litre saloons and coupes out there.
Insurance is another thing, i think it will be reasonably high being a group 14 car, how old are you?
I can't say i know too much about them, you'll have to read more reviews and take an average.