Most photo applications provides some way to toggle between the original (unedited) version of a photo and the current (edited) one.
In Aperture, "M" toggles between the two, many iOS photo apps let you touch the screen to compare the edited or filtered version to the original, etc.
I can't find any way to show the original in the new Photos app other than "reverting," which removes all the edits.
I don't want to remove them, I just want to compare the two.
I realize that I can "revert" then undo, but it's hacky, slow, and worse, dangerous - counting on undo to preserve work in any app is iffy, at best.
Note: The fact that Aperture edits are saved "less destructively" than Photos shouldn't be relevant here. Both applications DO retain the original, in edition to the edited version.