My comic-reading friends and I have a term called "continuity porn". If a story appeals mostly to longtime fans and contains numerous references to previous stories, it's continuity porn. It's a term mostly used in comics, but it can also be applied to other media as well (I love LOST, but it became continuity porn about halfway through season 2). It's also the reason I created this blog, to help potential new readers avoid it.
I honestly can't tell if the latest issue of Action Comics qualifies as continuity porn. It's a complete story told in a single issue, which is a rarity for most Superman comics these days. It re-introduces the Toyman after a long absence, and gives new readers a full history of the character. It also casts his previous appearances in a new light, and builds a second-tier Superman foe into a more credible threat. On the other hand, this comic makes it a point to undo a story from over a decade ago. Also, would anybody who isn't a longtime Superman fan even care about a story that focuses on a villain as obscure as the Toyman?
Misgivings aside, I enjoyed this comic quite a bit, and I would recommend that new readers go to their local comic shop, gamble $3 and answer the "continuity porn" question for themselves.