Not too long ago, someone made a wish that someone could do a comparison of the three main DB mods - A Brotherhood Renewed, Dark Brotherhood Chronicles, and Return of the Dark Brotherhood. I can't find that thread, so I decided to just start a new one.
I haven't actually played any of these; this is just an "in a nutshell" summary gleaned from the mods' readmes and looking at them in the CS. At the least, it'll provide a useful comparison for anyone interested in playing some or all of them. These mods are NOT compatible with each other due to their editing the same NPCs' AI*.
*ABR and RotDB *may* be; I can't compare them in TES4Edit because I don't have KotN or Vile Lair.
Brotherhood Renewed
Author: Arthmoor
Content
* 9 main quests. The storyline focuses on rebuilding/repopulating the sanctuaries in the other cities.
* 30+ named NPCs, 5 new sanctuaries. No items to speak of.
Requirements: None
Playing time: ??
Misc:
* No known patches/conflicts.
* Small file - about 8 MB.
Dark Brotherhood Chronicles
Authors: Amadaun and AndalayBay.
Content:
* 15 main quests, 6 side quests. The questline focuses on rebuilding the guild.
* 35 named NPCs, two full sets of armor, lots of clothing items, books, and weapons.
* Lots of new music tracks.
Requirements: OBSE and MenuQue.
Playing Time: ??
Misc:
* Has 3 patches for the UL mods, one for Open Cities, and one for ImpeREAL Forts.
* Huge file: 191 MB.
Return of the Dark Brotherhood
Author: Emerald Demond
Content:
* 17 main quests. All but the last two are contracts to kill a target, while the final ones deal with a(nother) traitor in the guild.
* 25 named NPCs, several sets of armor and clothing, and many reward items for completing the contracts.
Requirements: Shivering Isles, Knights of the Nine, Vile Lair
Playing Time: ??
Misc:
* No known patches/conflicts.
* Large file: 46 MB.
* Mod needs cleaning with TES4Edit.