I see most people choose them, at least from searching around. I don't need the house, I don't have an interest in the horse. If I kill Astrid I get the Blade of Woe right then, plus when I kill the rest of them I can have all the armor I want. Personally I find the set ugly, and wouldn't use it regardless of the nice enchants.
So other than achievements, and assassination missions, have I missed anything? I can make an alt to get the achievements, but I really don't feel like ruining my Wood Elf by joining them. He hasn't murdered anyone, and I'd rather keep it that way.
Seems better in my situation to kill Astrid, wipe them all out, and be done with them. I'm a thief, not a murderer, I do have standards!
You do miss out on one of the better Followers (the Initiates) and the Spectral Assassin, as well as Shadowmere, but I've never found the loss of those to be particularly problematic, and like you I never bother with the armour.
"We get serious about fictional girl underpants, and kid around when it comes to topics like world hunger." ~Teepo on CAGN
I usually just destroy them. It gets you into their hideout to learn the word for Marked for Death and I don't have to spend a bunch of time completing 'radiant' assassination missions for a pointless gold reward.
"We are what we think. All that we are arises with our thoughts. With our thoughts we make the world." - Buddah
If you do want the achievements you can just do like I did and create a save before and after joining, complete all the quests, then just reload to the save before joining and overwrite/delete the one you made after joining.
Never once have i destroyed them, you miss out on a GIANT chunk of content. You don't have to like the characters, but the DB questline is certainly better than certain other guilds.
What seems to ruin DB for most people is the patience that may be required for certain contracts, unless you don't care about bounties and just run in screaming. I understand some people will roleplay as a "good" character, and DB would interfere with that. And since me are too unsmart to figure out how to black out spoilers, i'll just say there are many ways to give yourself very real laughing fits when you get creative with your assassinations.
If you're gonna RP a good person, by all means, do so. Otherwise, join them. Telekinesis+potato= Wheeeee! (theoretically)
Kill them all. They are all horrible, badly written "characters" and should be removed from the game by any and all means available to players.
Technically the innocents that they kill are carefully selected by a god being as a necessary evil that NEEDS to be destroyed for the betterment of the world... they don't take every single prayer that comes their way. The nightmother chooses who NEEDS to die...