There are cambelt horror stories but it's very easy to avoid:
1) With the petrols you change the belts every 36,000 miles or three years, whichever comes first. For the waterpump you change every 72,000 miles or six years, as these are quite robust and are not prone to failure.
2) For the JTD diesels Alfa Romeo indicate 72,000 miles or 5 years, whichever comes first. However there are now emerging problems with the waterpump so it's a good idea to change the belt/tensioner/idler/pump at least every 60,000 miles or 4 years. Some independents recommend 48,000 miles or 4 years.
Apart from the usual regular oil checks and servicing these Alfas (any Alfas) are fine. ok you get the usual suspension replacements such as lower wishbones, but on our rubbish roads there's nothing unusual about that.
Hope you find a good one.