I recently bought Faction Pack DLC for Metro: Last Light.
I loved the original M:LL and I thought the DLC would be awesome as well. I was wrong... and disappointed too, it only features three short and (very) average missions.
I've downloaded user-made maps and mods that have much more content than this DLC.
I also bought "Rise Of The Triad" (the new remake). Haven't played it much but it looks OK.