Not to put too fine a point on it, but Chris Chase had a very different take on these in March of 2012 (and they're 4 years older now).
http://www.autos.ca/used-car-reviews/used-vehicle-review-lexus-gs-2006-2012/
He lists a litany of problems and complaints and ends with this cautionary warning.
"don’t complain to me if you wind up disappointed in what you were sure would be just another well-made Toyota product."
I remember how much this disturbed me at the time since this is a car I've always found very appealing. So, is Justin soft balling Lexus, or was Chris too critical ?!
The AWD (V6) GS brought the scores down. I wouldn't buy one.
The GS430 has been rated tops in Consumer Reports.
The original article mentions many issues (some serious) that are not related to AWD. Here is a sample including CRs assessment of 2007 on...
"The GS has, historically, enjoyed a “very good” reliability ranking from Consumer Reports, but that that changed as of 2007.
From this year on, CR gives the GS no better than its “average” used vehicle rating, due to a number of common trouble spots.The most common complaints include noisy brakes and interior squeaks and rattles, as evidenced both by Consumer Reports’ data.
In this discussion at ClubLexus.com, owners detail some of their DIY interior noise fixes. Many dealer techs seem to have a hard time properly troubleshooting the many unseemly creaks, squeaks, groans and rattles that the GS is known for.