Re: about to buy a 2011 but have a few questions!
The performance and mpg hit are simply due to the extra weight of the transfer case and front axle and drive shaft. There is a bit more friction too. So technically it will be slower, I dunno if you would notice it, but there is a bit of weight there. You would have more cargo and towing capacity with the 2WD, and the lighter weight may make it feel nimbler. With 2WD, you won't have to worry about keeping all the tires the same diameter
With traction control and 2WD, the rear will effectively be limited slip, as the system will apply brakes to the spinning wheel, which transfers torque to the wheel not spinning.
If the cars are about the same price, the 4WD version is a much better deal.
I'm sure you will be happy regardless. The value of the 4WD system is often a judgment call only you can make. It will certainly have more traction in wet or muddy conditions, and pull you through puddles better and more safely. It may also have a better resale value.