OK first I want to try keep this short as possible because you've already seen other reviews and the description I'm sure. So, in a nutshell is it any good? Yes, if you take it on its own. I've seen the comparisons to Twilight Zone, Outer Limits and Black Mirror and like those this is also another sci-fi/ horror anthology show. But can we just hold there for a second.
I read one review saying something along the lines of this is a terrible copy of Black Mirror, I don't agree. I really enjoy the former and I do agree, it's a better show. However, it is also much darker. An episode of Black Mirror can leave you feeling as if you just watched someone eat a puppy. Whereas Dimension 404 is a bit lighter in mood and subject and surely does not take itself as seriously. Same goes for the "Zone" and "Limits" we should probably compare 404 to one of the more comedic episodes of the Zone or better yet, the 80s anthology by Steven Spielberg "Amazing Stories". In broad strokes if you enjoyed Stories, I think you'll enjoy this. If you're looking for something a bit shocking and more thought provoking you can't go wrong with Mirror or some of those fantastic old Zones. Bottom line 404 uses differing methods to tell similar tales and after four episodes it's not my preferred method but, it sure is a very fun change of pace. If you're not 100% twisted 100% of the time you might enjoy it too.