There are some decent stories in a number of the post code Atlas's, and I noticed a proliferation of 5 and 6 stories in them, as compared to the standard 4 stories in the pre-code books.
My personal criteria is that a book have at least one story that I consider worthwhile to re-read again, or I dump it unless it has a cover that by itself makes it worth keeping . That applies to all comics, pre and post code. Although my stash of post code is quite small compared to pre-code, very few get re-sold, so the story quality did carry on to a reasonable extent.
It looks like all Atla pre code horror and post code suspense have taken quite a jump in price since about a year ago or so. 1955-57 books in VG are starting to go for nose-bleed prices from this tightwad's point of view, eh eh.