Not surprised. The Lexus IS line always had potential, but never really delivered. Toyota needs to at least offer a manual transmission version of the IS350. The IS250 is underpowered for all that luxury dead weight they pack in there.
I just bought four Blizzak LM60s for my G8 so I'll see how this combinations does before I consider a new SS. Then I'll make a decision between an Impala LTZ and the SS. The new CTS can get a little pricey with the V-sport option so I doubt that I will go that direction.
I really don't see any other under $50k options except those two. The Buick LaCrosse is getting old and I think the Impala is a much better car for a few less $$.
My repairs to date on the now five year G8 are a broken key fob so I'm not in the least afraid of Holden anymore.