I've learnt a lot about Alfa ownership since i bought my 02 reg 2 litre 2 1/2 years ago. Paid just over 5K with 51k on the clock. The cam belt went at 59k, that's when I found out about the intervals changing from 72 to 36k for the belt change!
Top end repair cost £1400, but got £1000 back under warranty. Bottom end wasn't done but had no trouble since. Needed variator done at 74k so had another new belt! If I'd known about the variator I'd have done it the same time as when the belt went. At 77k the thermostat went, resulting in overheating & a blown head gasket warping the head. Another £1300 down the pan! (£400 back under warranty) Had head skimmed & another new belt, but this time I had water pump replaced, cost around an extra £ 40 as I'd since heard they wear out from 60k.
In hindsight, knowing what I know now, when I bought it I'd have had the belt & balancer belts done, variator & water pump all at the same time & hopefully have avoided the expenses.
Having said that I love the 2.0 TS I thought about selling after the head went, but opted to keep it. If / when I do change it I'd get another Alfa, probably a GT.
The 147 is a bit of a hard ride especially on the 17" alloys, but it handles well, runs well & looks great. I think the facelift model is a bit of a softer ride, but I've never driven one.
From a buying point of view make sure it has a good history & if you're not sure don't buy it. There are lots around.
I have a 3 door & have used it with both my kids in although with a baby it may be a bit trickier.
I've never regretted buying mine, except I wish I'd held out for a leather interior.
The only other issues I have really are wheel alignment tends to go out quite regularly but the number of speed humps round here doesn't help, oil consumption varies but mine uses around a litre every 1000 miles. Oil consumption improves I found if you use Selenia racing oil.