I was disappointed with the fact that it wasn't the steelbook edition and that Arkham Knight is just a code and not a physical disc like Asylum and City. Now, if you're not a collector and don't care about having physical copies like me, then you probably won't have any problem. In other words, you should buy the Return to Arkham plus the code.

Now, onto the positives:
1) The first two games in the series have been remastered, so the textures and overall graphics have a big improvement compared to the original copies.
2) Although Arkham Knight is a code, it comes with everything available on the PS store for free. This includes challenges, races, all the skins, and the story DLC session of infamy: most wanted, which adds some extra hours of gameplay.

To conclude, yes, I recommend it if you don't mind the aforementioned drawbacks. However, if you have a problem with them, I would suggest getting the Return to Arkham and the Arkham Knight premium, which together are not significantly more expensive than this