I got the MB470 which is the lower end new MBP, I've tested it with a Nikon D700 with the LR tethered plugin by mountain-storm, it worked perfect, same speed as my bulky PC. However I find the LED display a bit disappoint because just a little off angle would result in very obvious hue/brightness shift. Maybe it just should be like that, since I don't have a previous MBP model I can't compare, and I don't know if the display just got worse. But I'm sure if someone wanna use this for a color-critical works instead of just a tethering laptop, he/she would be f***d up.
Edit: I got non issue except the display, however the display is not indeed bad, it's just not that good, compare to my monitors for retouching. And yes maybe I shouldn't expect so much for a 2.5 kg laptop...