i think most consider 904l to be a little tougher than 316l when it comes to scratch resistance, though it's close. there are different measures of scratch resistance from a materials science perspective, and it's a bit of a toss-up when comparing those two depending upon exactly what scale you are looking at and who is producing the steel. but most rolex watches hold up a bit better in that department compared to your standard, cheaper 316l case. that said, the primary reason rolex uses 904l as i understand it is because of it's increased resistance to corrosion. comes in handy when regularly exposed to salt water and in those tiny recesses of a case (like where gaskets sit) where water and/or salt might collect or sit a bit longer than normal.
apple reportedly cold-forges their 316l to be stronger than the average run-of-the-mill 316l. you can do a number of different physical things after the fact to make the same chemical formulation stronger. but they aren't doing anything that makes their SS cases THAT much more scratch resistant than standard steel watch cases. but they do seem to be better at resisting big dings and dents. that might also be a function of the rounded, polished surface.
mine is in great shape but that's because i have it wrapped in an Armor Suit. Same with the crystal. however, as i have reported elsewhere, somehow the ceramic back has obtained a couple of small, mysterious scratches, which is a shame. they're odd, though. i can't feel them even when i run a piece of notebook paper over them. it's like they're either too small to be felt in any way, or under the surface. but under a loupe they clearly reflect light in such a way as they appear to have depth and be true scratches. and they won't polish away. i don't believe they are transfer marks. my ocd will obsess over them for a few more weeks and then hopefully i'll settle in and be able to live with them
just wabi-sabi, as the japanese say.
when looking under the loupe i also detected some extremely small marks on the tiny uncovered areas of the steel (like on the crown and the pieces you push to remove the bands. but overall the watch looks great. and as has been said many times, a cape cod will buff it back to a wonderful shine.
