the "LED bleed" on white s3's only affects the capacative menu and back buttons (which anyone with any sense switches off once theyr familiar with the buttons) and the notification LED
as for it getting dirty, for some reason all of my phones get dirty at the back top right corner (left if ur lookin at it from the back) and ive no idea why... think thats the place i touch LEAST on the phone???
back on topic though, the white has such a gloss on it that it wont pick up stains or anything. i think the white is the lesser of two evils.. its easier to make it look nice with a case or whatever.. id love a gun-metal black version though