In theory, both orders work in their own way.
However, I think it's better to play them in release order, as their storytelling is quite independent and it's pretty easy to follow the timeline in their stories.
The big advantage of the release order is the steady improvement and expansion of game mechanics. If you play Origins first, Asylum will be a step back.
Despite this, Arkham Knight is harder to sort chronology, since it includes a few story DLC's exploring both the past and future.
TL;DR: Play the games in release order. DLC always after the main game, except the Harley Quinn Story Pack - play that before Arkham Knight.