A lot of enhancements for new design of reddit.com like unwrapped feed buttons, bigger fonts, view images without redirect and many more...
I never used old.reddit so I not so mush understand, but I did it for comments. For posts maybe later. By default the bookmark shows only for an comment which already saved. To show bookmarks always you need to go in settings and uncheck "Hide unsaved bookmark" option.
+1 this one, it would be great to have the save post button quickly accessible like this!
please unwrap the 'save' buttons, like in the old reddit!