It all depends what you want to do, ride both gs and GSA on the same day, my first exposure to both and opinion was, short, nippy ride, go gs, longer ride and touring go GSA. I am 1.88m and 106kg, f800 feels like a 650 on steroids to. Again it all depends what the purpose of the bike is.
2012 to 2011, I will not buy them, my suspension broke and I know two more which broke while there were 2010models in the same situation, which experience the swingarm problems, the 2010 has a DOHC engin and the rear swing arm does not break as easily.
I do not want to start a brand debate here, but there are other options and manufacturers to consider as well.
For myself, the GSA does the trick, everyday commute, once to twice a year long trips and some one day trips, finally the odd weekend trip. If I did not tour with the bike I would have considered the ktm 1190r, triumph is too small for myself and Yamaha s10 is a great bike and very durable, but the new price tag is too high.
I will stick to the k51 for a long time to come, inspite of an fd failure, which cost myself dearly recently.