It seems as if the ATS-V is following a somewhat similar path, although it's unlikely it will appreciate in value over time like the SS will. Even so, I've been seeing a number of them (ATS-V's) relatively close by on Auto trader with significant discounts, priced at about 54k USD, which is exactly where the top trim G70 is gonna be I bet. It's very tempting, as not only does it have more power, but legend has it there are even a few with manual transmissions.
Even so, I still like the looks of the G70 quite a bit more, and the AWD is a big bonus, thus I'm still leaning towards the G70.
Such hard decisions, life is rough. /sarcasm.