I would also say that the DB had the most enjoyable quests out of the guilds I have tried so far, though I thought the last Thieves' Guild Quest was quite interesting.
I don't know how it exactly happened, but I couldn't complete all the Fighter's Guild quests, right after Modryn gets fired, he tells you to get missions from the two usual Stewards, I did the two immediate missions from the Orc but then Azzan didn't have any missions for me, after that I couldn't raise rank or get any missions from anyone, depressing
