Having some buyers remorse here. Sold a mid 2011 13" Air to upgrade to the base rMBP. Running at the highest OSX based resolution (not using SwitchRes) and the lag is annoying. On any graphical pages such as Facebook, it is noticeably jumpy compare to the Air and Windows desktop I have.
Just installed Mountain Lion Dev 4 and was disappointed it's about the same performance. The three finger swipe up to show all apps struggles and is also choppy. Other small complaint: as thin as this is, it is still a beast compare to the air.
3 days left to decide if I want to return this and go with the new model 13" air...leaning towards it...
Does the lag go away at "best for retina" resolution (1440 x 900)?