They are cool little cars but the prices of them have lost all relevance to their actual value in terms of fun/coolness/rarity/performance/etc...IMO.
Ancient design, poor performance and mediocre styling but still a very comfortable and well made car in the most German tradition. If this sounds like I don't like them, WRONG! I just think that they are cool $2500 cars in average condition with no rust, like they've always been here in CA. until recently. They are the furthest thing from rare. The later ones with huge bumpers and lights are close to valueless, again IMO, because they are missing the little bit of style and performance that the earlier ones had.
You have to remember that they came out in the mid-'60s and by the mid-'70s were an obsolete model cobbled together with emissions crap and crash bumpers, just basically a place marker in the showroom until the new e21 came out.
I've owned a couple, (bought them cheap when young and broke), I think they were sweet little cars but really nothing special at the end of the day. Alfas of the same era were extremely exciting in comparison.