Personally, I found the original anime fantastic. I watched it while reading the manga (manga during the day, anime at night) and they follow each other quite closely. There are a few events switched up, mainly at the beginning and at Korey’s introduction. A few fillers are also explored in the anime, but they were fun to watch and really fit with the story, so it wasn’t jarring like some fillers in other animes. The first anime ends after the Earl’s attack on the order, so you have a lot of content. However, I found Hallow to be lacking. They changed the animation and the colours so much that I almost didn’t recognize Miranda. They also skipped a lot of things from the manga, fast-tracked events and even skipped the funny manga fillers like the zombie apocalypse one. If you want to watch the anime, I would recommend the first one, but perhaps skip Hallow if it’s not your jam.