In recent years Buick has found it difficult to distance the brand from the “senior citizen” stigma.  While the Regal GS looks elegant, yet sporty, it cannot quite be considered true competition for other brands due to the price tag and almost confusing projections Buick has released for the car.  The GS is a decent car certainly.  The ride is remarkably smooth considering its ability to hug the curves. The brakes are outstanding, and the driver receives consistent handling even under harsh driving conditions. I was not keen on the delay between pressing the pedal and the car actually accelerating. It is great at speed, but the waiting to get there leaves you wanting.
Updates for the 2012 model were extensive, yet mainly performance related.  GM says the Regal GS can lay claim to having the highest specific output of any production engine it's ever sold, which is good.  The boosted V6 engine didn’t meet North American emissions regulations, so here we are reviewing yet another 4-cylinder with a measly 270 

horsepower and 295 lb-ft of torque.  Britain’s equivalent, the Opel Insignia OPC gets a 2.8L V6 with a twin-scroll turbocharger making 300 horsepower, as well as all-wheel drive.  Something else consumers were a bit disappointed in.  We North Americans get cheated and receive the front-wheel drive.  But that’s neither here nor there.
As far as the interior, it has been said, and I concur, that it is your typical “GM look”.  A bit boring honestly with the usual black and grey.  Some color would have looked much nicer and would add a lot to the look.  For the GS to be an “upscale sports sedan”, it does not deliver in the features department. You are paying more for a GS, when the competitors’ versions are considerably less expensive.  Being that Buick is trying to break out of a mold it has been in, either lowering the price tag or offering more high-class appeal should have been obtainable.
If you are one of the few devoted Buick fans, there is no doubt you would love this car.  There may be a few others that might as well.  All in all, it is a good ride.  If you don’t mind spending the money, that is.