Check Consumer Reports for objective rather than anecdotal reliability ratings. You'll likely find reliability to be below average, but whether that matters is another question since most cars these days are actually quite reliable, and individual cars of course vary from sample to sample. If well maintained, even cars with low reliability ratings are probably not going to leave you stranded by the side of the road; oftentimes reliability relates to complicated electronics (Merecedes is chronically dinged for this) which are associated with convenience features but which don't prevent the car from being driven.
Alfas are often viewed as attractive designs with good handling, a minimal dealership network, and unimpressive general reliability (with the caveat about "reliability" noted above). They are not terribly popular, so depreciation is likely to be worse than average, of that matters.