Bang for buck is pretty good on Alfas, but it's not the primary concern, I guess - an Alfa is an Alfa. It's designed by people who are willing to sacrifice some practicality for style, some efficiency for driving fun. Of all cars, it's the one you really can't evaluate from a spec-sheet.
There are quite a few Audi drivers on here, and they've never said "I really wanted a Porsche". An Audi is a very clear type of product - it appeals to you or it doesn't - and so is an Alfa, BMW, FIAT, or even Skoda.
SEAT's problem is that they can't yet answer the question: "What kind of cars does SEAT make?", so that leaves people with no attachment other than the price and features list. They're good cars on paper, but they're not reliable enough and not stylish enough to compensate for it. Ironically, VW's "Why have 'like a Golf' when you can have a Golf" ads applied to SEAT more than to any other carmaker.