So far everything about the SS is better than my 08 G8 GT. The drive, road noise, technology, power, controls are all at a higher level than the G8 was. It should be though it's 5 years newer than the G8 was.
Looks, they both have good parts and bad parts. At some angles the G8 looked awkward but overall it is more aggressive. The SS had an executive car look and I have not seen a bad angle yet. The SS also has aggression but it grows out of the car rather than being obvious.
The SS will stay in my garage for a long time, even if they introduce a M6 in the future. Being one of the first to own the car is very cool and it draws looks on every road I drive.
I don't regret one Mile trading my G8 in for my SS.