When I first got my GSXS i thought the front forks were excellent and the rear shock was lacking in control.
Having upgraded the rear to an Ohlins GP TTX shock the rear was hugely improved and now the front end didn't feel so good.
So I have just revalved the forks with K-Tech SSK piston kit, big improvement - you can really feel the difference with just 1 or 2 clicks adjustment. Seems plusher and more controlled. More information here