i prefer driving the calais too. based purely on feel and the creature comforts. i own an sv6 and brother owns a calais. the sv6 feels 'slightly' quicker in acceleration, and feels like it breaks better. it could be, or it could just be the harder suspension playing tricks on you. coz you feel more in touch with the road.
i love my sv6, but im a poor bastard so i cant boost it, not going to kid myself into thinking its fast, and doing lil things here and there, not much point. unfortunately i didnt think like this when i bought it, but hey its still awesome.
im just getting old (;-p) and am very impressed with how smooth the softer suspension is in the calais, and how pretty it is inside,leather, good air con, good factory sound system etc.
sv6 still looks better outside imo
at the end of the day, they are both mad cars, but comfortability helps win my vote for calais.