I've been using mods since day one and my game only ever crashed twice (and one of those times was when I manually deleted patch 3 files to fix a quest broken by said patch). That is to say that mods can cause problems, but for the most part they are not game breaking, especially if it's simple cosmetic stuff. Just make sure to have a separate save before installing a mod in case it does mess up your game somehow.
As for the character origin, the dark urge has a fully customisable appearance and its own story.
Personally I much prefer custom origin because I want to be able to come up with a backstory myself, but I see how for some people it may seem lacking. My first playthrough was on a tiefling sorcerer and quite a few quests felt personal. My current character is a human fighter and while I do seem to get fewer race/class specific dialogue choices, it still feels different to my sorc because I play her as a character with a very different mindset.
