I'm riding a 2012 1200GS now after an 1150GS, a KTM 640, 450 and a string of other bikes. Once properly set up (I ditched the silly ESA suspension and added a 21" front wheel) the bike is seriously capable off road. I have ridden Baja twice from tip to tail and crossed the country on two different GS's and a ZRX1200. This new 1200 GS is fantastic. Mine is down to 460lbs with gas so if you avoid the Touratech catalog these things can be lightened up considerably!
Have fun and enjoy, they are great bikes but so are many others. We are truly in a great time for adventure bikes as consumers since there are several excellent players for us to choose from.
Cheers, James