As someone who has not yet read the LNs or seen any artwork before I discovered the anime, I absolutely loved Ariel's design especially.
Definitely, definitely read the LNs, instead/first. The anime spoils a lot of the mysteries and seems to think that the main point of the story was a bunch of fight scenes that have no build up and seem to have Kumoko pull powers out of her ass since they don't bother with the discovery sections. You're missing a huge part of the point of the story if you watch the anime, which involves trying to piece together what happened behind the scenes in an anachronic story and one of the better shounen fighting style "learning to use the same power for new tricks" style of action.
